Update: So unless the test is at 8AM tomorrow (in which case, dilution is my only hope - I smoked today, and every day leading up to today for about a month) I *think* I can push it back to Tuesday or Wednesday, in which case I am seriously interested in trying substitution.

I do not have access to someone who can provide me a clean sample (at least not right now), so I'm hoping I can find a place to purchase some synthetic urine - but have no idea where to begin. Any help?