This article is from the Credit cards and Consumer Credit FAQ, by email@example.com (Steve Adams) with numerous contributions by others.
Be careful when applying for credit. Some companies advertise
credit cards on TV. The problem is that although the card looks a
lot like a Visa or MasterCard, it is only good for merchandise from
the company's own catalog. Despite the promise of "discount
prices," you will pay more than you would pay in stores or through
other mail-order channels.
Most legitimate catalog companies take Visa, MasterCard, American
Express, or some combination. You should always pick merchandise
for its own qualities, not because you're forced into it by which
credit card you have.