Yeah, just to add an alternative to the 'don't pay upfront' crowd... I paid £4.5k upfront to an established and long running school at a Class D airport. That banked me around 35 hours of C152 time. It was great knowing that if the weather was good and the instructor was available I could walk the 400metres from work to the school and go flying, or when I was doing solo circuits I could pop out during my lunch break and get some time in.
Meant I didn't have to worry about funding anything for a huge portion of my training (in fact, I only needed to find 5 hours extra at the end).
I know why people say 'don't pay upfront' (the school may close unexpectedly / you may not actually get on with the school's training methods etc.) but for me it was key to me getting my licence.