Each Saturday there's a food market in Temple Bar from 10 am to 4:30 pm. It used to be in Meeting House Square and I expect it'll return there, but at the moment it's scattered across several locations.
One of the stalls is The Temple Oyster Bar, currently located on Cow's Lane. A "single shooter" is €2, but they also offer platters of oysters accompanied by soda-bread and white wine. There's a wide range of the condiments you'd expect, such as tabasco sauce and lemon.
This was my first time trying oysters. I love seafood and this was the most marine-tasting thing I've ever eaten. I liked it, although not as much as I like sushi or sashimi.