What's the cheapest source of nitrous oxide and equipment for recreational use?

Paint is not a controlled substance but it is not legal to inhale paint either. You are wrong mediaskate. Don't talk about something you know nothing about. Wishing you were right or that the law made sense is not the same as it being correct and the law.

go to home hardware, and buy those small air canisters that some bike racers use to fill up their tires very quickly.
also get a whipped cream DISPENSER not actual whipped cream(that way is way more expensive)
put the canister into the dispenser, using the dirrections that came with the dispenser.
inhale, and enjoy your trip:)

I agree with this question, purchasing nitrous in those dumb tiny canisters may be expensive, but it's really the safest and best way. I have found that it's best to try to get them in bulk on the internet, you can get em for about $0.25 US a piece. Is anyone a dentist? how is medical grade nitrous controled?

Whipped cream.

It is done by puchasing whipped cream in the metal cans that have the plastic nozzles. DO NOT SHAKE. Take the UNSHAKEN whipped cream can and hold it straight up - preferably leaving it on the floor or table. Push the nozzle and inhale. This is lovingly referred to as a Whippet.

The nitrous is used as a propellant so once it is gone the whipped cream will come out slowly and be gross and is basically useless.

So, in short, have fun. (And remember, only do what you know you can take. It is possiable to be allergic to nitrous oxide, I am.)

It isn't techinally controlled (it actually is completely unscheduled on the federal level) Buying for human consumption is illegal as is inhalation of it without a "qualified" (dentists who are technically qualified are not anithesiollogists and can often... botch the prosedure by not giving you enough oxygen) to supervise and of course for a mecdical reason. It is legal for anyone to posess it, though, so making any charges that a person is a user is almost impossibe without catching them in te act. Supply companies do not sell it to people who aren't doctors, because if a person were to consume it recreationally they could be prosecuted. When people do get it in bulk it's usually from a "friendly" dentist or person who works for a medical supply company. That or it is simply stolen. It can also be obtained from autimotive supply stores that sell NOS systems for use in cars. I'm not entirely sure what the manufacturing standards are for those canisters, but I can say with a fair amount of certainty that they would not be safe for consumption.