better yet, dont price parts at all? auction them, that's what ebay is for. 20 buck reserve no buy-it-now option, let people pump up the bids.
I hadn't used ebay in a long time when I auctioned some items before Christmas. There was little bidding activity and it was very challenging to make my auction stand out among all the imported Chinese junk without paying for extra Ebay bling. After the auction was over I was surprised to be billed a percentage of the shipping charge... something I'd never been billed before. It was very frustrating since I don't mark up shipping at all. I have a bunch of stuff to sell but after my last experience I'm not too keen on that venue.