Your typical ratcheting tie downs. These are from Home Depot, I bought them for $13.97 for four. The strap clamp that they sell comes in a one pack and costs 12.97.
Cut the strap off of the ratchet and the hook off the other strap piece.
Sew the long strap on to the ratchet with a box and a "X" through it where you cut the original strap off.
That's it now you finish the other 3 and you have 4 ratcheting strap clamps for about $15 and 20 min of time.
Strap clamps work on numerous projects I use it for holding the legs together on a stool while waiting for the glue to dry. Also can be good for drawers or picture frames and other odd shaped items.