I recently picked up the Meguiars Clay bar kit for under $20 (with 2 clay bars) this was a first for me but I found the job to be easy enough to not be discouraged from doing the whole car. It does make a difference! I was somewhat amazed to see what came off this clean car. I followed it up with the Ultimate Paste Wax and couldn't be happier.
Don't be afraid to try it, it wasn't difficult to do at all.