I got tired of buying air in cans for dusting typewriters and such, so I rounded up an "Intex air pump" (Google it) that came with an inflatable mattress.
It seems to do a decent job although the air blast is not quite as strong as canned air, but sawing off the smaller diffuser that comes with it gives a good push to a 1/4 inch column of air. And you can move the nozzle to the suction part of the pump for a vacuum.
Mine runs on four D-cell batteries, but they make models for 12- and 120-volts, starting around $7 -- or free if you already have an air mattress.