There are a fairly decent number of "reputable" dealers on ebay, just follow the auction and fixed price bullion items for a few weeks and always check the feedback.

Using your CC through your paypal account means the seller will absorb much of the cost and should cost you nothing additional.

Your best bet will be if MSN Live cashback comes back anytime soon. If you can get a 20-30% rebate you will be able to get your bullion at below spot prices.