My husband’s grandparents have stayed in I think it’s the Comfort Inn in Scarborough for a lower price and found it clean and comfortable. You have to drive ~15 minutes into downtown Portland but you’ll be closer to the beaches.

You won’t be able to stay anywhere in Portland for $200/night. I don’t even know if the hotel I suggested would realistically be $200/night during the summer. Browse Airbnb as well and keep an eye out for deals, is the best thing I can suggest.