if you can't afford WFP at present, then get yourself a set of ladders, as a newbie you will never make a go of it with extension poles and traditional window cleaning.
Pole work on standard windows upstairs can be done, but it takes real skill, you will make a real mess of the windows if you attempt it.
Ladders are NOT illegal yet! The majority of window cleaners work off ladders, you have to know how to use them and understand the Health & Safety regs, but you really can't start window cleaning without them.
Shops you can almost forget, they are the hardest fought over work around, particularly if you are a complete newbie, if you can get enough bungalows then you can at least get underway, but you will still need a pointer ladder.
Work beckons...gotta go
Ian