Etymotic Research ER-20 Earplugs for $13

Hearing protection is important for music appreciation, which brings us to the Etymotic Research ER-20 Earplugs offered for $12 plus $1 flat shipping at the members-only Massdrop service. But if you are a Prime member, they are offered for $13 with free shipping (or the usual $49+ for non-members) by Etymotic Research with the orders fulfilled by Amazon. Note that at Amazon multiple options are sharing the same review pool, so you must dig into the review page and filter the reviews for this specific model if you want to read more about it. There is no option to filter the review scores though.