So, let's say if someone wanted to roll their own, they could get Reaper and an XNA subscription -- maxing out around $150, if I recall, which is a pittance compared to the "discount" price of $1000. After that, any sales you make on RBN are all yours. Be a smash hit or be something someone occasionally picks up, either way, you'll very likely trump your initial investment and the rest is gravy.
Say you DON'T want to roll your own. Tag with RA or a similar company, again, zero up front, and gravy all the way home. RA are the ones taking the risk, but it's balanced -- if they get enough songs in the works, the ones that sell subsidize the ones that don't, and again, the up front cost is minimal for them (time investment, mostly, not much cash investment).
This is not a good deal, period. It's old media thinking, that you have to blow massive amounts of money on an ad budget in order to get anywhere.