Slacker Premium is $9.99 a month and it includes the ability to play albums on demand or single artist stations, as well as creating your own playlists. Slacker Radio Plus is $3.99 monthly; it offers the preset station but lacks the ability to customize your own.
If you're looking for your own music service, consider some of the following issues:
Which service is compatible with your device? Anymore, most streaming services offer mobile applications across most platforms (like iTunes, Android, Windows, etc.). However, purchased songs bought from one store don't always play on a competitor's device. Check compatibility before you invest.
What do you want out of your service? Do you want to stream preset radio stations or design your own with songs and artists you choose? Are you looking to buy music or just listen? Do you want it to stream through your mobile device or your computer?
How much do you want to spend each month? There will be more ads and limitations with free services. Check the services' websites for more details and price points.
Are your favorite artists available on the services you're considering? Do a search. Explore the genre. Make sure the ones you like are on that service. Be wary of your mobile data with these streaming services. I think I would use them much more if I had unlimited data with my wireless carrier, which I don't.
While it's hard to distinguish one choice from the next among streaming and discovery services, music lovers now have good ways to discover their next favorite artists.