I'd argue that it's exactly the other way around. GAE offers massive scalability at relatively little cost, at least theoretically, but you lose flexibility. (

I'd argue that it's exactly the other way around. GAE offers massive scalability at relatively little cost, at least theoretically, but you lose flexibility. (For instance, you're limited to a very specific database backend and so on.) A cheap VPS, on the other hand, gives you free reign. But scaling isn't trivial - you have to take care of it yourself. Learn and fiddle around on a VPS, deploy on GAE or EC2 or whatever cloud computing service suits your needs.