The center market sure is saturated right now so I wouldn't be surprised if it didn't cost an arm and a leg to get one. That said, the majority aren't in the upper tier. They're borderline 1's/2's but mostly 2/3's. Still, there's upgrades to be had.
Let's use the Kesler deal as a benchmark:
Bonino+Sbisa+late 1st
Bonino is a promising but unproven young forward, Sbisa is a decent #4/5D that has pretty much topped off, and a late 1st is a late 1st.
IMO Wilson in the the area code of Bonino, Ellis is better than Sbisa, and we have plenty of things worth a late 1st.
Guys I'm looking at: E. Staal, Spezza (if he'll waive), Thornton (if he'll waive), Stastny (UFA), ROR, Skinner
Backup options: Roy (UFA), Sedin+Sedin (too expensive to acquire and old), Brad Richards (UFA), Mike Richards, Grabovski,
Worst case scenario: Ribiero, Lecavalier