I used to think foam earplugs suck because they didn't fit into my ear. Turns out you have to roll them! Sadly the first time I encountered foam earplugs in a library they didn't include instructions. Rolling them they get thin and easily fit into your ear. Once I knew this they became my favorite earplugs to use during sleep. I used to use reusable ones, but the problem is those inevitably fall out of my ear onto the ground and get dirty. Same happens for the foam ones, but they are cheap (mine cost 0.25 USD/pair), so I just grab a new pair if they are dirty. They lose their elasticity after a few uses, so you cannot use them too often anyway.

By Fornax, CC BY-SA 3.0