According to ESPN's Pierre LeBrun, the asking price is a second-round pick (which is how much Bishop cost the Sens a year ago) as well as a roster player or good prospect:
Asking price on Ben Bishop right now: 2nd-round pick with eithera player or a prospect— Pierre LeBrun (@Real_ESPNLeBrun) April 3, 2013
That seems like the asking price that's been rumoured for some time now, so it makes sense that it comes out now. Still, it's unclear whether or not Craig Anderson is ready to go yet, so dealing one of the team's good goaltenders might put the team in the lurch heading into the playoffs.
However, Bruce Garrioch has said that the Sens have had a number of teams inquiring about him:
Lots of interest in Bishop: PHI, EDM, CAR and TBAY have all inquired. Sens would like a player and pick in return. #TRADETRACKER— Bruce Garrioch (@SunGarrioch) April 3, 2013
It's unclear what type of player the Senators are looking for, but they're in need of defensive help (although Jared Cowen would be pretty good in that regard) and could probably use a proven second-line player.
The benefit, of course, is that the Senators are in the driver's seat here: Bishop is set to become a restricted free agent, so there's no rush for Murray at the moment. He can afford to wait until the off-season or draft day or even later than that, if need be.
We'll keep you posted on the developments.