Improvisation
Lab equipment can be expensive, but it's not impossible to use certain household items as lab equipment. It's possible to replace many things in the lab, from glassware to entire processes.
Glassware
Boiling chips
Ceramic shards, such as porcelain (unglazed are recommended) can be used as boiling chips.
For better chemical stability, sandpapered glass shards are also better, as they will not react with acids (except hydrofluoric and hot phosphoric acids), but will react with hot alkali and degrade less. It's necessary to sandpaper them to create a rough surface, as normal glass is smooth, inadequate for creating a boiling surface. Since glass types are between 5-7 on the Mohs scale, you will need abrasive sandpapers that are higher on the Mohs scale (the black type for example, containing silicon carbide, is good).
Boiling/anti-bumping chips can also be produced from crushed high-quality quartz geodes after being treated with acid. The rough surface of these actually protects against bumping more completely than many lab-grade boiling chips.
Büchner funnel
Coffee filter funnels, usually made of aluminium or stainless steel (rarer), found in certain coffee makers can substitute Büchner funnels very efficiently. They are however unsuited when filtering corrosive substances, such as acidic or alkali solutions (the stainless ones are more resistant to the latter), so they are more suited when filtering organic solutions.
Consumable aluminium beaker
Aluminium cans are more heat-resistant than glass beakers, as they don't tend to shatter on intense heating. The top can easily be removed with a can opener. This is not recommended for use with oxidizing compounds. Large hollow aluminium capacitors can also be used, and since they're thicker than aluminium cans, they deform less when heated. It should be noted, though, that aluminum will react with many acids, sodium hydroxide, and many solutions of metal ions, such as copper(II). Therefore, aluminium beakers are more useful in organic reactions and somewhat useful when dealing with nitric acid. One must be careful when using nitric acid however, since any traces of chloride ions in the presence of acidic protons will dissolve the aluminum. Since aluminum does not have a high melting point, it can melt if overheated.
Desiccator
Any plastic or even metal boxes than can be sealed airtight can be used as a desiccator. Large plastic storage bins, such as this one, available at many stores and hypermarkets are cheap and can be easily made airtight. The wet material can be placed on the bottom of the bin, while the desiccant can be placed in the superior part on a support, as the water vapors are lighter than air and will rise.
Instead of a plastic box, large reclosable bags can also be used. If the bag is too small, you can cut the bottom of two bags and tape them both. This also has the advantage of allowing who openings, where one can be used to introduce the wet material, and the other for the desiccant. While cheap, the main disadvantage of this method is that the bags are easy to poke, which can ruin the dry atmosphere inside.
Distillation kit
A solvent can (like the kinds used to store acetone, methyl ethyl ketone, and n-heptane) can be attached to a metal pipe, bent over into a collecting vessel. These kind of metal retorts are actually preferable to glass for producing and collecting substances such as benzene and phosphorus. The main problem is their tendency to react with products. One may have trouble with the production of metal chlorides, nitrates, or various coordination complexes if the reagents to be distilled react with the apparatus.
If you do have access to glassware but not to running water, there is a few ways to improvise. The simplest way is to connect an air-cooled condenser such as a Vigreux column instead of a normal condenser. This works best for high-boiling liquids (and for the very high-boiling ones such as sulfuric acid, this is indeed the best option even if you have running water). Another method is to use a water pump in a bucket.
Dropper
For most liquids, a drinking straw may be used as a dropper. Placing a finger on the top opening while the bottom end is under the surface of the liquid allows the straw to be lifted from the liquid while retaining the liquid inside the straw.
Filter paper
Coffee filters are sufficient, unless you need smaller size pores. Colored coffee filtered may however interact with certain organic solvents. Tea bags are also good and have high wet strength. Air filters can also be used.
Light bulb flask
Carefully cut light bulb glass can be used as a flask, and is quite resistant to heat, though being very thin means it can break very easy and it might not be able to safely contain a stir bar. High pressure sodium bulbs however are much thicker and may be used just like any other piece of glassware.
Scoopulas
One type of tool used in jewelry making and repair resembles a scoopula. It is available at Hobby Lobby for 50 cents. Various spoon-like plastic-ware from ice-cream shops may serve well as replacement scoopulas. Small scoopulas may be made from straws with L-shaped cuts at their ends.
Stirring rods
Glass bead kits often come as glass rods, which can be used out of the box.
Test tubes
Vanilla pods are often sold in glass tubes with a plastic lid. Similar tubes are also found in many bargain stores, as containers for incense sticks. Usually there's two of them, bound with a sticker.
Plastic or glass test tubes can be found in many stores, used for storing flavors, spices, as well as many other non-edible products, such as toys. Martha Stewart test tubes are a good example .Test tube shots can sometimes be found in many clubs, bars and pubs, used for shot drinking.
Many brads, such as Jägermeister, not only sell plastic cylindrical shot tubes, but also other types, such as rectangular tubes and even tube racks of various sizes, made either from foam, metal, plastic or acrylic. Other alcohol product companies sell similar products.
It is important to remember that most of these test tubes do not handle thermal shock as good as lab test tubes.
Watch glasses
Literal glasses from watches or clocks can be used as watch glasses. Most however tend to be flat glass disks, and may pose problems when holding spherical particles. They are also not heat resistant.
Carefully cut wine glass bottoms can also be used, however it is extremely difficult to flatten the wine glass leg stub. A much better idea would be to add some support to keep it straight.
Conveniences
Miscellaneous
Heating elements
Kitchen stoves, portable cooking/camping hotplates, alcohol burners, and even candles can be used for simple reflux setups or dissolving solutes. A metal plate or grate can be placed over a well-controlled fire to obtain very high temperatures, which may however break glass. A sand or an oil bath can be placed on the metal plate. When boiling flammable solvents, avoid using an open flame.
Microwave ovens can also be used for heating chemicals directly and more homogenous.
Storing containers
Ordinary food glass jars can be used for storing many compounds, however, they are unsuitable for storing volatile compounds, as the lid, usually enameled or painted metal is not resistant to corrosion and may contaminate the compound with rust. Use plastic lids instead, such as PP or PE.
Metal coffee containers, such as the ones used for coffee, cocoa, tea, cookies can be used for storing non-hygroscopic and non-corrosive compounds. Stainless steel food containers can also sometimes be found at hypermarkets and are good for storing various materials, except for corrosive ones.
Old large siphon/soda bottles are a good choice for storing volatile chemicals, due to its narrow opening, large body volume and can tolerate high pressures. They can be used to store volatile corrosive chemicals such as fuming acids, liquids with low boiling point, etc. A PE, PP or even PTFE lid (if you have one) can be used to close the opening.
Water aspirators
For vacuum filtering, Venturi injectors, available at agricultural shops, can effectively replace lab water aspirators.
Video
A significant portion of the ideas came from myst32YT's video of lab tips:
