I bought a set of the custom molded earplugs at Walmart and they surprised me at how well they work. For .22 shooting they will be fine.
Radians Custom Molded Earplugs
They seem to work for me when I'm on the range by myself or with a few other handguns. But the other day I got dropped into the rifle range because they were busy. Standing in the stall next to a guy shooting a Mossberg and a AR-15 made them feel lacking. My wife had a set of foam plugs and normal earmuff style cans and it was difficult on her too.
But normally, they are fine.