Do you have the Apple jam packs? They come in 5 different varieties...
However, if you wanted to get jam packs 1-4 a cheaper way would be to buy logic studio! It comes with JP 1-4, Sound Track Pro, Mainstage, Compressor and much much more!
There are other places you can get apple loops. Depends on the style(s) of music you are interested in.
For example, Martin Sitter (of macProVideo - the Logic 101 tutorial) has a site called Audiobase:
There are sample libraries there in Apple Loops format.
Also google names like "Producer Loops", "Apple Loops" and visit TimeandSpace
Hope that helps :-)