This site has the absolute cheapest testing kits I’ve been able to find anywhere – we’re talking dirt cheap. Do some comparison shopping (especially with your local pharmacy), and prepare to be shocked. They carry any kind of drug test you could need, including peripherals like adulteration strips, specimen cups, gloves, etc.
They market to people like employers and parents, so you won’t find any fake penises or dodgy detox kits here. Anyone can place an order, but to avoid any awkward questions I always order online instead of calling their toll free number. If you place your order before about noon Pacific time, they ship the same day (and their shipping is dirt cheap too!).
This link goes directly to the page on Erowid’s site where you’ll find the detection times for all classes of drugs.
There are lots of websites on the Internet that have information about how long different kinds of drugs stay in your system. But most of those other sites probably used Erowid as their source. It’s an amazing site with more information than you could process in your lifetime. Some of it is getting a little out-dated now, but still one of the most reliable sites on the Internet. Marijuana Policy Project
Anyone who smokes pot should be aware of these three organizations. They work tirelessly on our behalf, with the ultimate goal of one day seeing pot legalized. Visit their sites and consider supporting them.