Not particularly SAS related so I'm not sure if this might get removed.
Yes, I have participated in a Clinical Trial. Since it was done during chemotherapy as part of treatment there was no payment. Drugs provided for daily dose for basically a year but whether they were placebo or actual I don't know. Considering the known side-effects of the chemo the potential ones listed for the trial drug were a very minor consideration. Since the drug involved had been around for awhile the likely side-effects were pretty well known.