Corner Clamps

While casual browsing over the last couple of days i found a couple of corner clamps for woodworking which were pretty good, unfortunately they cost $31 a pair and they are not available in India. See above.

This got me thinking, can these be made locally itself. The steel that I would need to use would be spring steel. I havent yet figured out where i can get it. The corners am using some lumber that I am going to get professionally cut to be perfectly at a 90 degree angle.

If anyone has any idea about corner clamps or the particular one above. Please do let me know.