Beats -- $4.99
You really can't buy too much with $5 these days, but Beats offers gamers a robust rhythm experience for less than the price of lunch. The game detects every song on your Memory Stick and converts each one into a level. The beat dictates when you hit each button, which can come from all four sides of the screen. The trick is to hit the button along with its respective direction on the D-pad. Bonuses include a tutorial to help you get started, online play via infrastructure mode and even tools to create your own music.