(AP) -- EBay Inc. is rolling out its eBay Bucks shopping reward program to all U.S. users of its online marketplace.

The program, which had been in a limited "beta" test, gives participants a 2 percent reward on certain items they buy through .com and pay for using eBay's online payment service, . The rewards are issued as quarterly gift certificates, which can be used within 30 days when using PayPal to pay for items on eBay.

Participants can get up to $200 in eBay Bucks for each item bought on eBay, and as much as $500 per quarter. If you bought a $100 vintage toy, for example, you would earn $2 in eBay Bucks toward your quarterly total.

The program's adoption marks another move by eBay to improve the shopping experience on its main site in hopes that it will attract and retain buyers and sellers - something it has been focusing on by implementing a slew of changes.

Marc Steffans, the program's senior manager, said eBay decided to expand the program beyond the test Wednesday because it noticed that participants often used their eBay Bucks very quickly after receiving them to buy other things. That's a sign participants were pleased to get rewarded for shopping, and it helps sellers, too.