I don't use Mac but use Napoleon Perdis. I love the loose powder which has the extra shimmer.

I know they can be expensive but have you checked out Ebay? That's where i get my eyeshadows from at a fraction of the cost. Have you spoken to your local Mac dealer about becoming a regular? I did and got a 10% off everything card. With my card in mind, i bid on NP stuff on ebay. If it works out to be cheaper on Ebay i purchase, if not, i use my 10% off card and purchase through the store.

I know it's addictive.