So you would like to try your hand at some biohacking. Professional labs cost hundreds of thousand of dollars to build from scratch, but you can get started for around $500 or less with a little improvisation and patience.
Let’s start with the pieces that will take up the biggest chunk of space in your lab: refrigerator, freezer, autoclave, and incubator. If you are just planning to run through an educational biotech kit at home, you can probably get away with clearing some space in your kitchen fridge. However, if you are planning to do more than just a weekend project, then invest in a dedicated fridge and freezer for your experiments. The vast majority of educational kits out there are perfectly safe, but the average novice might not realize that some classical experiments (like isolating unknown bacteria) can be hazardous to your health if stored near food. Plus, you will eventually need the extra space anyway, and it will protect your experiments and edibles from cross-contamination.
Mini fridges can often be found on Craigslist for less than $50 — or free on Freecycle. If possible, avoid the kind that has a tiny freezer compartment at the top — they get iced over and are too small for practical use. Instead, try to find a mini freezer that is the same size as your fridge or get a 2-door fridge/freezer combo. Many modern household freezers have an auto-defrost feature that briefly warms up the cooling coil a few times a day to keep ice from building up. The resulting temperature fluctuations can be detrimental to sensitive biological materials such as restriction enzymes. Check if there is a way to disable the auto-defrost circuitry or simply put your enzymes inside a styrofoam box in the freezer.
An autoclave is essentially a big pressure cooker that heats growth media or equipment above the boiling point of water in order to sterilize them. Guess what — a regular pressure cooker makes for a fine autoclave as well. In a pinch, you can even use a microwave oven to sterilize growth media — just watch out for flash boiling! When you are ready to upgrade, professional autoclaves are surprisingly easy to find on Craigslist. Aim for one that is at least 7″ in diameter so you can fit decent-sized flasks, and expect to pay a few hundred dollars.
An incubator is used to grow cells at a carefully controlled temperature. You might be able to score an old egg incubator or yogurt maker at your local thrift store. You could also simply build your own by putting a heating pad with a thermostat in an old cooler. Pet stores sell heating pads intended to keep pet reptiles nice and toasty.
A centrifuge is really useful for concentrating cells out of a liquid culture, separating DNA, proteins, and soluble components in complex mixtures, and more. Biohacker extraordinaire Cathal Garvey (@onetruecathal) designed a 3D-printable “dremelfuge” that can be chucked into a Dremel power tool to turn it into a centrifuge. However, unless your 3D printer is well tuned, they are prone to shattering at high speeds. You can order a high quality dremelfuge from Shapeways, but for that price you can also buy a cheap centrifuge on eBay. Inexpensive Chinese models running around 4000rpm can be had for $50–100, or 10,000rpm models for around $150. (You can also 3D print your own centrifuge using these instructions).
A commercial gel electrophoresis rig can cost a few thousand dollars, but it is essentially just a DC power supply and a plastic box with two electrodes. You can make a dirt-cheap electrophoresis power supply using a hardware store dimmer switch and a bridge rectifier. The gel box itself can easily be made out of dollar store plastic containers and a stainless steel or platinum wire for the electrode (check out this $21 gel box design by Cheapass Science).
You may also want a PCR (Polymerase Chain Reaction) machine. Again, commercial gear can cost thousands of dollars, but there are several DIY designs available online, and OpenPCR even sells an Open Source Hardware PCR kit for $599. Like most biotech hardware, a lot of used gear from professional labs eventually winds up on eBay or Craigslist. The independent online biohacker store The Odin has been buying up inexpensive, used PCR machines and reselling them after refurbishing.
You will need some way to generate a sterile field in which you can manipulate microorganisms without fear of contamination. An open flame from an alcohol lamp or Bunsen burner will do for starters. A simple laminar flow hood, often used for mushroom cultivation or plant tissue culturing, blows ultrapure HEPA-filtered air over the cultures. If you want to get really serious, you could upgrade to a biosafety cabinet instead. Professional labs often leave their biosafety cabinets behind when they move, so if you cultivate the right contacts and are willing to put in some serious elbow grease, you may be able to score one for free.
To manipulate small but very accurate amounts of liquids, you will also need a set of adjustable pipettes. Cheap Chinese pipettes can be bought from The ODIN and a few other places for around $40 a piece — you will want at least two or three different sizes to transfer anything from single-digit microliter droplets, to several milliliters.
Other smaller items you will need include digital thermometers, a few small digital scales with a resolution of 0.01g or better, boxes of nitrile gloves, and a variety of glassware and plasticware (check your local dollar stores!).