Valencia as a starting third baseman would be a mistake. If AA is serious about that, then they are mismanaging their roster. Valencia is a great bat to platoon with Lind since he could also play 3B, 1B and LF in emergency, so he'd be valuable on the bench as well when Lind is in the starting lineup.
If they want to go cheap, I'm sure someone like Denorfia won't break the bank, same Aoki and Smith. As for help either at 2B or 3B, I could see Headley being a bit pricey, though I'm sure Cabrera, Drew, or Lowrie could be acquired at a decent price.