My band is loud, and our stage volume is just stupid. I use inexpensive foam earplugs with a very high (29db) noise reduction rating. I love them. My ears feel fine at the end of the night.
Of course it does not sound the same when we play -- the high frequencies are dulled, and whenever I sing my voice sounds disproportionately loud. But it only took a few weeks to realize that I CAN hear the rest of the band just fine. It only took some getting used to -- the brain fills in the blanks for you once you get used to it, and the music honestly sounds good, full, and dynamic. I can hear myself sing every time regardless of monitor mix.
I got my earplugs on ebay and paid less than twenty dollars for 200 pairs. I use one or two pairs each night; when they lose their resiliency they don't work as well.
I tried the Sonic earplugs, the little 6db peak-reducers with the diaphragms you can get for 12-15 bucks at a music store. They were awful -- ineffective and uncomfortable at the same time. I wore them twice and threw them away.
I may try a form-fitted pair someday -- I used to believe that was the only kind worth trying, after my bad Sonic experience.
But for all you guys who don't want to try earplugs because, like me, you thought they have to cost a lot to be any good -- try the high-rated foam ones for a month to get used to the new sound. Maybe, like me, you'll find they are all you really need.