I swear by this! I use this inside and outside my home. It's a natural and safe way to prevent or kill ants, fleas, bed bugs, roaches and more. Cheaper than other places for more.
Harris Food Grade Diatomaceous Earth Powder - OMRI Listed for Organic Use, 4lb Bag
You don't necessarily need this for the powder, but it helps a lot. I do have one. If you don't want to spend the money, you could probably try an old squeezable water bottle. You need something that puffs the powder out rather than shoot or pile it.