I used foam inserts for work, they only go so far and some peoples voices are impossible to hear or very muffled..

These are very reasonable, and can be found for $40-$70 range Audio-Technica ATH-ANC23BK
QuietPoint® Active Noise-Cancelling In-Ear Headphones

They help lower noise even if turned off.....If you also have sensory integration problems they help a lot of that sound activated goofy things.