I have followed this topic on other sites over and over again. Allofmp3.com is NOT legal in the US- period. Anything they say or you say to justify their legality is simply rationalization. They pay NOTHING to the label or artist for royalty. They have no authorization to copy the music they have on their site, let along resell it.
The fact is there are several foreign governments who could care less about US intellectual property laws. China is one, Russia another. In Russia it is estimated that well over 95% of all computer software used in that country is pirated. We used to joke about this that there must be some kind of lottery where the loser has to buy the new software and everybody else gets a free copy of it.
You can try to rationalize this by saying you are paying for it, but you pay something for stolen property it is still illegal to posses it. Will you get caught? Who knows. Probably not. This does not make it legal however.