well... everything i have downloaded is free... cuz i'm cheap :P these should all work (i recently lost my blackberry and got a replacement, so i've checked these recently). i installed all of these in less than an hour.
anyway here's a list of stuff you can look up (sorry i don't have the links).
GOOGLE - go to Mobile and download the updater. you can pick and choose which google blackberry app you want. i highly suggest the maps, if nothing else.
OPERA - it's a great mobile browser that renders webpages to make them look more like they would on a desktop
GAMES - look up the following:
- Outbreak Control
- THK2 (Texas Hold-Em King 2) NOTE: THK3 is available too, but not free
- Medieval Kings Chess 2
- Handmark BlackJack
- Spider Solitaire