If you have free time at hand during the week and you find a clinical study which fits your criteria, you can make good money for your participation time. You might only be required to be at the clinic for a short period of time, performing certain required tasks for example taking mental evaluation tests, giving out blood for testing, or taking an MRI scan of a body part.
If you are afraid of giving blood or going under an MRI machine, you might consider a different kind of a clinical trial.
There are many clinical trials available for different experimental drugs. You can find out which company is performing these trials and where are they taking place. If you live near a research hospital or a university, you might be in luck. These institutions have these studies going on at a regular basis.
When you sign up for the study, you would be required to fill out a consent form for your participation in the study. You will have to take full responsibility if anything goes wrong with you due to the drug reactions or side affects of different procedures performed on you.
Usually your compensation to participate in the study would be paid weekly or biweekly. You should check with your clinical co-ordinator for exact details of compensation paid to you. Many times the compensation is in the form of some coupons or vouchers for a vacation. Make sure you ask in advance to prevent any unpleasant surprises. It is always a good idea to read the contract in detail before signing.