Despite having been to Vegas at least 100 times, I never made my way to Tacos El Gordo until just recently. It's located in a strip mall about a 5 minute walk past Encore on the strip. The tacos are $2.00 and the carne asada fries are $10.00. Portions are pretty good - don't expect anything too fancy. There's limited seating inside but plenty of tables outside. The way it works is you go to the corresponding booth for what you want to order, put it all on a tray, and then pay after. Food is pretty good but I had a terrible experience.
One downside to this place is that it may or may not have gotten me food poisoning. Considering there's close to 1000 reviews on this place, I may have just been an oddball but I was in a sweaty, chilly pain a few hours after eating here praying all night long to the porcelain god in the hotel and vomiting 16x. Since this was the first thing I had in Vegas, I subsequently didn't get to indulge myself in any other food or alcohol for the remainder of the trip.
You've been warned.