I have been told by various people that re-using plastic bottles, such as gatorade bottles, is bad for your health because they leak chemicals. I will re-use them once then throw away.

From a quick google search this was what I found on re-using plastic bottles.

Even Plastic Water and Soda Bottles Should Not Be Reused
Health advocates also recommend not reusing bottles made from plastic #1 (polyethylene terephthalate, also known as PET or PETE), including most disposable water, soda and juice bottles. According to The Green Guide, such bottles may be safe for one-time use, but re-use should be avoided because studies indicate they may leach DEHP—another probable human carcinogen—when they are in less-than-perfect condition.