I have recently bought myself a 2010 Fiesta Zetec S and I want to put a performance back box on it I don't want to spend a lot of money but I want it to be top quality what do you guys suggest?

There's no such thing as a performance backbox

 

Also there's no such thing as cheap and top quality I'm afraid! 

The 1.0s honestly sound like ***** cannons without a factory or decent custom exhaust system (jm talking from experience) 

 

You'd be better saving for a high quality one or putting the money into other modifications such as LED upgrades with autobeam Or something 

i got lucky i found a bloke who was selling a ST180 back box and downpipe to the resonator, i only put the back box on, it sound good and looks good too, he wanted £70 for it as he had a custom one put on and wanted rid of it, i offered £50 and he accepted so, it was a fairly brand new ST it came off, have a shop around and have a look at viseos, like kieran said if you save money go custom as they can tailor make your exhaust to what you want.