no premium fees and the 4% back is why they're flying off the shelves at Costco. Also, people are intimidated by going to a gold shop to buy, they don't know what they're doing and are worried about getting ripped off. Costco has one of the highest trust factors in all of retail, so people feel comfortable with Costco's value.

If you buy, check your state's laws regarding any sales tax. In CA, you pay tax on precious metal purchases under $2000, but no tax over. Which is easy when it comes to gold (if you buy 1oz or more), but if you buy silver, make sure your total purchase transaction is over $2000 or you'll pay tax.