[quote name='Outinthedark']Anyone have any tips regarding Rock Band Blitz and adding some cheap songs to my inventory? Are the old games have some sort of import code (I have never played them just see them traded a bunch) so that you can play them on RBB?[/QUOTE]
The cheapest per song is to import the other games. You can import RB1 (about 50 songs) for $5 with the code in any manual and the disc. RB2 has a one time use code and costs $10 for ~50 songs plus two 20 packs (making it ~90 total). Lego Rock Band has a one time use code that lets you import it's set for $10 (I think this one is closer to 45 songs). Green Day is the same, $10 for 45 songs. Other than that, you have to go with the track packs (20 songs each, one time use code in the manual, ACDC, metal, country, country 2, TP vol1, TP vol2, classic rock) or individually downloading songs (from $1 - $2 per song, discounts on packs) from the marketplace. There are a SMALL handful of free tracks through the marketplace, but those are few and far between.
For anything other than RB1 though, you're taking your chances buying used; a lot of people bought the game, maybe played it or not, imported and then traded it in, and the codes are only good once (except RB1).