The only difference is, ESPN NFL 2k5 came out for $19.99 when a new retail games cost $49.99. Live 13 is coming out for 19.99 when a new retail games cost $59.99.
So this is actually a better deal than ESPN NFL 2k5. 2k you were getting for 40% of the original price and Live your getting for a third or 33% of the original price.
Can we really complain? Especially when you don't "have" to buy the game.