Legal M.usic Help

We want to arrange that our members of our site can listen to 30 seconds sample of music tracks from Famous (copyright) artists. So who can help us with a license or know a company who can supply license for listening or only 30 seconds. Have anyone a good solution for this? 2 important issues: -must be Legal -solution must be cheap eg WHITE LABEL Supplier of copyright music Pls send us details examples how to solve this, thank you very much, and we keep in mind your help because we have many projects to be done, so the better you help us, the more chance we deliver you many jobs.