Coilovers / lowering springs

[Callum1997]

Hi I've recently bought an a3 (2007) 2.0 TDI sline don't really have a great idea as to what I'm doing when It comes to this told it was best to use a forum and get some help I'm after some coilovers/lowering springs that fit but not a clue where to start looking as I don't want to be paying too much. I'm also unsure as to where would fit them if I did find some. Thanks for your help