Best FPS for PS3? ($20 and under)

Ok so I've been looking at some games lately, and so far I can't choose between Call of Duty 3, Crysis 2, and Modern Warfare 3. I also want some suggestions, for best [MULTIPLAYER] because I rarely go through story anymore (in shooter's). If you have any suggestion's, I'd appreciate it.

Note: I used to have MW3 for Xbox but I traded it with my Xbox (and Black Ops 2) for an HD PVR, and I've played the beta for Crysis 2 (on story mode, nobody was on multiplayer, and I figured that was because its a timed trial?)

Either Crysis 2 or MW3. Call of Duty 3 is very outdated, and the player base is crazy small. I'd go MW3 for the players, but Crysis 2 had better multiplayer overall.

Try looking into MAG or Killzone as well. The exclusive shooters are a lot better than the multi-platform ones, I find with PlayStation anyways.

Deus Ex: Human Revolution - It is $15 on Amazon and even cheaper used. Buy this gam. BUY IT.
Borderlands 2 - MY 2012 GOTY
Battlefield 3 - The best FPS multiplier experience you will find on the PS3.
Killzone 3 - Great single player. I enjoyed the multiplayer though I am not sure if the community is still strong.
Bioshock - Arguably one of my favorite games.
Bioshock 2 - However! I read that you can download Bioshock 2 for free in the PSN Store... I do not know if there is any validity to this, but check there first.

I did have Amazon links for you to each game, but I only just realized that, as a new member, I cannot post links. Best of luck to you.

Thanks for the comments, I picked up Crysis 2 & Modern Warfare 2 in the end, and to Ciel, I will be checking on the PSN store for Bioshock 2, thanks for the suggestion

It seems to be only for PSN Plus members.