値段が安い店って英語でなんて言うの？

When something is not is not expensive then we can say 'inexpensive', 'low priced' or 'affordable' You can add restaurant to explain what you are talking about

If you wanted to refer to restaurant that is not very expensive, you could refer to it as a "Budget restaurant". The word budget implies that if you are restricted with money and need to budget wisely when buying food, this place would be good for your budget. You could also refer to it as a "Low-priced restaurant" or a "Fast food restaurant", as fast food is generally very low priced.

The three words you see provided above are great ways to describe an inexpensive or affordable restaurant. The second word, budget-friendly, and the third term, easy on the wallet, both mean cheap. This word and this term are appropriate for informal settings, like talking with close friends or family. It would make a great addition to your vocabulary.

All three of these answers are names that are used for inexpensive restaurants. Most cheaper restaurants are located in towns or city centres. Their prices will be low for a number of reasons. Perhaps the food quality is not that high. Maybe the staff are not waiting on tables and are not highly trained or paid. In Amsterdam there is a fast food outlet that has no members of staff at all. It is called FEBO.

If you are talking about a fast food chain you can simply call it "fast food" because it is implied that it is cheap and affordable. "McDonald's is a fast food chain."