DHEA doesn't really do anything if you are taking it on its own, you have to stack it with several things to see some serious effects. And even then stacking does no good if you are not working out. Lots of working out and lots of protein are the only real way to go.
DHEA is considered a steroid and was about to be banned a few years back with many other steroids, but someone along the way said it was useless and wouldn't let the bill pass unless DHEA was taken off the list. It is technically the only legal steroid left in the USA that can be bought without a script. However it is really just a pill full of sugar compared to real T. You will get very few changing effects, if any at all, and they will be nothing close to what you would get on T.
There are plenty of "testosterone boosters" out there, and you can take all that you want, but nothing is going to happen unless you are taking HUGE amounts, and by the time you start seeing results you would probably be saying goodbye to your kidneys or liver as well.