welcome to ANTRX,
I would like to direct you to the search function found towards the top right of the screen. You will find it very useful if you are looking for information. In future, consult it before posting, as sometimes you can find some very cranky ANTRXers who would be happy to flame you for asking a question that has been covered before on various occasions.
Using a search I have discovered:
the cheapest way would be to get Pedders springs. but they aren't as stiff as some and might be prone to sagging. Also try king springs, they are cheaper than whiteline but are not as saggy as Pedders.
as far as wheels go, as long as you don't change the outer diameter of the wheels then you shouldn't have a problem with a lowered car. Also, if you are considering larger wheels down the track, then leave a couple of inches space.