Here in the USA, they are at Walgreen's. Right next to the candy bars and other high impulse buying stuff next to the register. They are single use tests and test for a number of drugs. If your testing for cannabis, the results will show like a pregnancy test. If your testing for other things, you need to mail the sample to the company and they send the results...part of the price of the kit.
Drug test kits are available on-line. Google for what your looking for and you should find it.
