CD's are just a promotional tool for live performances. There is not much money in either of these, it's the by-products that generate the real money, i.e. publishing royalties, radio, DVDs, posters, t-shirts etc. It's the hype around the band, the product that creates earnings. Basically a record company will pay you and advance of say, $50,000. The recoup earnings based on album sales, promotions, management etc., depending on what type of contract a band has signed. So out of that $50,000 you might only make $25,000 if you're lucky. An album usually has to ship >500,000 units for the record company and the artist to break even. Anything over that point is when the money cashes in.