This was another spot I visited while I was in Portugal that was *not* on my list - a truly…read morewonderful seafood restaurant around the corner was, that I got to before noon because I wasn't sure when they opened (turned out: 12:45 that day), so I was wandering around with an hour to kill and found this place. They have flights, including one that's 15 euros where you let them know what you're looking for and they pick out the 3 bottles, which is very neat. I told them I was in Porto mainly to try Port wines, and didn't have much familiarity with other, non-fortified Portuguese wines, and would love an intro flight, but no roses. Got a mini-lesson in the wine regions of Portugal, along with a wonderful green wine, a great Duoro valley red, and a truly fantastic red from Alentejo, a wine region I had not previously heard of, but immediately went on my radar the rest of the trip. (They also sell bottles; I bought a bottle.)
Note, they said they only guarantee they'll do flights (as opposed to full-priced full glass pours) after 4 pm, but if they aren't busy for the food lunch rush, they'll do them earlier in the day (on a rainy Thursday in January they were more than happy to.)
Actually liked the place so much, I came back the next afternoon and had another glass of a different Alentejo red - they only had one open for tasting in the price range that fit the "intro"-priced wine flight, so I spent... I believe 11 euros on a glass of a fancier bottle they recommended. It was also quite good, though I think I actually preferred the first one. Also had one glass of a very reasonably priced tawny Port while I was there - they had several, but obviously, I was already well into my plan to taste Port directly from all of the nearby tasting rooms across the bridge, so I just picked one here. (Unsurprisingly, it was also quite good.)
They do also sell food, but I can't comment on it. Great place for quick wine tasting, though.