I went on a taco trek, and while it looks a little worrisome from the outside, the champion taco in Tijuana for me thus far is from Taco Bell(no not THAT taco bell). On the walk to the Arch from the border, this run down local shop that serves a very limited menu. If you are feeling brave, I love them. The staff is always friendly and the tacos are the best we have found the area. They have two types of tacos(I think around $ 2 for three tacos?) and cheap($ 1.00) beer. I have eaten here multiple times and my American stomach has never had an issue with them. I don’t go to Tijuana often, but this place has been there for at least 7 years, and it’s time someone gave them some love.