According to the list visible on Xbox360Achievements, 250G will be hidden in the game's multiplayer section. Whilst it hasn't been confirmed, we're pretty confident that the trophy list for the PS3 version will be identical.
Other multiplayer achievements mentioned include winning matches in every mode, getting your hands on all upgrades and characters, reviving team mates and being the sole survivor at the end of a match.
While the game's single-player is being handled by Crystal Dynamics, the multiplayer is the responsibility of Eidos Montreal. The studio has been keen to emphasise that the multiplayer won't be tacked-on and will actually be a substantial part of the game which, if these achievements are anything to go by, appears to have been the truth.
We recently got a chance to go hands-on with the multiplayer, and came away with quite mixed feelings, especially over the rather lacklustre Team Deathmatch mode, but felt slightly more positive about what the Private Rescue games might offer. On the plus side, at least the game won't feature an Online or Season Pass to further inhibit your hunt for that Platinum Trophy or maxed-out Gamerscore.
Tomb Raider will be available on Xbox 360, PS3 and PC from March 5.