Our local HD had these in one of the "impulse buy"/gift bins in the
main aisle. 4 for $20.

How the gods must chuckle at us poor beasts and our deficient
allotment of hands; two is never nearly enough. I've had six of the 6"
QuickGrip Mini-Bar Clamps for a number of years. The clamping force is
limited, of course, but they have helped even the odds between me and
Physics in many a home-repair adventure. Sometimes the jaws aren't
quite wide enough though. For my purposes, two for $10 would have been
an even better deal, but I'm sure I'll use all four eventually.