Two buy-low candidates who might be worth getting if you have the luxury are LenDale White and Vince Young.
White is nothing more than a joke to many owners who think Javon Ringer is going to run him out of town. This is possible if White doesn't stay healthy, in shape, or focused at being what he's capable. But based on talent, Ringer isn't on the same plane as White - and I personally have never been a LenDale White fan (I let loose a long string of curses when he was drafted). But I personally believe that his value is at a good point to acquire him with Chris Johnson's breakout, the addition of Ringer, and the fact White fumbled the game away against Baltimore. The fact White is in much better shape and really steamed about his mistake is a good sign.
Let's remember that Chris Johnson is a dynamic player, but I doubt the Titans think he's a 15 carry per game back. I would think the injury in the Ravens game validates that notion and the resulting addition of Ringer was a reaction to it as much as White's play.
If White comes into camp in great shape and plays like he's capable, the Titans will not hesitate to feed him the ball and use Johnson as the change of pace and slot guy. Not that Johnson won't get his, but I could see White really doing a lot more in the 4th QTR of games and busting runs of 15-20 yards more often than we'd ever expect at this point.
Young is more of a buy low and sit on him for a year. I remember Broncos and Steelers fans who thought Elway and Bradshaw were going to be unmitigated busts. If there is a team that is going to seriously give Vince Young a chance to grow up and be the kind of man and player he should be, it will be Tennessee because of a) the investment they made in him and the potential they saw as a rookie and b) because Jeff Fisher is a straight up kind of coach who will look a player in the eye and say "this is how you are messing up and this is what I expect from you." A lot of coaches either play games are communicate these things in stupid ways that alienate or confuse their players. Fisher won't do that and this has given Young a chance to figure out that he just has to do what he's told and focus. It took him longer than what many expected, but I think at the cost you can probably get him by early in the regular season, he's a low risk-high reward value.
I like the Mark Clayton choice and I discussed him as a breakout candidate in an upcoming Gut Check Column on Stat Profiling Breakout Wide receivers that will be on the homepage in the next day or so.