Read the rules: NO PRICES. (the rules are in my signature)
This is 110% not what Other Drugs is here for, so please don't do this again.
You would probably want to eat several tablets if you are taking them orally; 5mg isn't that terribly high of a dosage.
If you have never had this sort of drug before - I would start with one and see where it gets you.
If you have taken plenty of speed before, or any dosage of amphetamine, i would expect to need 2 pills to 4 pills for a good dosage minimum.