I'm going to throw a random name on here that could probably be affordable.
Luke Kornet.
7'1", 250 LBS, played for the Knicks last year.
His main selling point is his ability to shoot threes and a growing ability to block shots. Rebounding might still be a concern, as he averaged only 3 rebounds a game in 17 minutes of game time last season, but his last month of the year has shown that he could improve that number by averaging 6 boards in 27 minutes of gameplay for April (he also logged in 2.7 blocks per in that month).
I know he's not a sexy name, and he's probably not the Center we want if we are trying to compete, but there's some decent potential there, and he's shown some growth in his two year with New York. With our limited budget, it's worth a shot.