Go on your local Craigslist and sort by price, lowest to highest.
There were dozens of companies in the 1970s who made bikes fitting your criteria. Looking for something specific, at your price point and experience level, is a great way to overlook possibilities and end up disappointed.
If you just want something to ride, fit (size) is far more important than manufacturer. A bike from a famous maker like Peugeot or Raleigh in the wrong size is useless to you. A bike the right size by a company you’ve never heard of would be great.