the goal of wearing a mask during an outbreak is to keep your personal exhaust fumes from spewing across the room, so any mask that doesn't do that job won't be approved. single layer gaiters, ones with exhaust ports, etc have shown to not be effective at the task at hand.
the Vera Bradly masks have come highly recommended by random people I've chatted with. everyone says they are quite comfortable. My mom just today got one for her birthday so I can give some more detailed experience in a bit. you don't have to get a flowery pattern like hers, they come straight up black too. If you want a disposable paper variety, the cheapest packs of 50 I've found have been on ebay.
I can't comment on the infinite variety of masks out there because I tend to be allergic to most all clothing and the masks are no exception so I don't even try them on. I run paper for short term use like in a store and then for all day use I have a couple custom masks made by a friend using one of my Jockey t-shirts (literally the only brand of undershirt I can wear).