Fat Burners / ECA

If all of the fat burner supliments on the market are all based on some form of ephedrine/caffine stack,why would you not just buy a bottle of aspirin, a bottle of caffine pills and a bottle of ephedrin and take them yourself (it would definatly be cheaper). Why would you buy a pre-mixed suppliment like hydroxycut. If you do take a caffine pill and an ephedrine pill, then is there a maximum length of time you you should take them before going off of them. I ask this because I have seen manufacturers comments on bottles of ephedrine that say you should not take them more than 7 days in a row. Any help from the t-men out there would be greatly appreciated.

to tell u the truth, when i first started training i used to make those homemade cocktails of vivarin,a minithin and aspirin. but to tell u the truth your better off buying a premaid package. the withdrawal headaches i received from taking this homemade formula were horrible. I never went crazy on the dosages but i think my body had trouble getting used to that much caffeine from the vivarin and ephedrine from the minithins. Just spend the extra cash and get the formulas that have the Yohimbine or ALA if possible. Anyway that just my take on it.