Reasonably Priced Hotel
Do you want to spend $50 or do you use that price because, based on your experience, that is a clean, basic hotel?
For $50 a night in SD you can do better than that. What do you want besides a clean room with bath? Do you want a pool? Air conditioning? cable TV? What are your minimums. If we know that, we may be able to direct you to some hotels that will cost you less than $50 a night.
Ken