I believe there's some info in the FAQ thread about purchasing MAC other than from MAC.com.
I don't know about any sites that accept paypal except eBay -- I've never purchased from anyone on eBay. But I use my CC to purchase from:
Gloss. com
Nordstrom.com
Macys.com
These are the main ones I buy from. In 2006 Nordstrom and Macy's had an exclusive which was not on the regular MAC site and I was able to purchase from their online sites. Also, I notice Nordstrom carries some DC or LE items long after they've "disappeared" from MAC.com, Gloss.com and Macys.com. I was able to get goldenaire and steel blue pigments in addition to fiction ES, to name a few things. In November Nordstrom also brought back all the sundressing shadows and I was able to get a back-up of sea myth and waternymph from the Lure Collection.
Also, I believe when you reach 20 posts on Specktra, you can check out the "for sale or swap" threads. There are members here who accept paypal.