Understanding online music stores
We've put together this guide to help you sort through the a la carte music store options, though we also touch upon the subscription aspect of certain music services. a la carte refers to a store where you pay per track or per album, then own that album, whereas most subscription services essentially rent out tracks for your listening pleasure. (As a subscriber, you also have the option to buy individual tracks outright, sometimes at a discounted rate.) Some subscription services even let you take this rented music to go on approved portable devices. For the complete lowdown on this type of music service, see our guide to on-the-go music subscription services.
Although most stores are in the midst of switching to all DRM-free MP3 catalogs, some sell music in a format that is only compatible with a particular player. Your first step in choosing a store should be determining which stores are compatible with your portable music player, since online music stores won't give refunds if you find you've made a mistake later on. The general rule to keep in mind is that (most) songs purchased from iTunes play only on the iPod, while songs purchased from other stores play on all other MP3 players, but always make sure to check a service's Web site for compatible devices.