Great topic. Really it's all about savings for my family. I put a couple hundred away each month for my pin fund. The fund includes LED's and repairs as well as a new pin savings. I found after you have a couple of pins you mostly trade out or up. Craigs list is a good site to get the occassional great deal.
If you could learn a little about basic repairs and playfield touch up you could possible make a little more money on your trade in's.