I got my onset of tinnitus while wearing foam earplugs. At the beginning of my tinnitus, I also tried a few sets of the popular brand earplugs purchased online. I did not feel much protection and would not trust them. My molded earplugs I trust 100%. They're the best $200 you can spend.
My ENT and Audiologist both informed me that foam earplugs aren't as effective in general, especially when worn for long periods of time, such as a concert. They move around and can come loose. They also caused my eardrums to become impacted with earwax, because they don't breathe well. They also told me he's had other patients come to him with the same issues after wearing cheap foam earplugs.
I had used foam earplugs in bands for many years, so I had plenty of experience inserting them properly. it wasn't even that loud and I was a fair distance from the stage.
There's a lot of information I don't trust from my doctors, but I'm just giving you my experience. I would not recommend anyone put their trust in cheap ear protection. This I can attest to.
Read my reply above to
@RunningMan. People can put their faith in whatever they want, I'm just giving my story on foam earplugs.