I'd recently been looking at some Fast Action Ratcheting Bar clamps from Penn State Industries
Cost me $22.96 plus tax. To get 4 - 24" bar clamps from Penn State (they make 12, 24 and 36 inchers) would have cost me $15.80 plus $6.50 shipping, or $22.30 all in - but no spring or C-clamps. The $6.50 would cover shipping for as many as you want though, so the prices would be much better than Wilton if you were buying in bulk.
Quality remains to be seen.
JP