Diatomaceous earth will do the job. It can be purchased at any farm supply store for pretty cheap. Works on fleas, bedbugs, millipedes, roaches, centipedes ... pretty much any little bug with an exoskeleton. Farm supply store because it's traditionally been used to mix into agricultural feed (food grade DE) as an anti-caking agent.

But works to kill bugs, too. Diatoms in this form are fossilized like microscopic weapons of destruction that get under the exoskeletons of ants and other creepy crawlies and dehydrate them. Best of all: no chemicals involved so they cannot develop resistance. Medieval torture devices on bugs; will desiccate them.