Average run time for the stock battery is about 2-30mins. I bought mine on ebay.

You have open up a very good topic to discuss here. There are two groups of battery users: LiPos and NiMH.

I am still using NiMH just for the ease of use I guess. I use Onyx 5000maH - this lasts me more than an hour of running time.

LiPos are better but I am not ready for them yet. Many users of these will tell you the pros and cons.