I agree that some record pools are expensive. However, if you really dig you can find some legal record pools that are free to use. For example, I found one called Digiwaxx, which specializes in Urban and Pop music. I noticed that they have a good combination of mainstream and indie and unsigned artists. The only thing they require is for you to send comments to the artist and review the track itself.
To me I feel that is good because not only does it give the artist feedback but it also helps you to how to critique music and developing your “DJ” ear.