What cheaper games to ask for christmas?

I have to come up with something for my sister to get me for christmas. I'm getting her a record or equivalently priced item, so no more than 20 dollars, i'd say.

I have a pc, a ds, and a 360, and I want to ask for a game that's cheaper. Please make some suggestions.

old stuff

old games are still good

get old used games that have been marked down to like $5