Do you want a PCB fabricator, someone to make empty PCBs for you? Or are you looking for someone to assemble parts onto a board for you?
Getting populated boards is a two step process, but there are companies that will manage the whole process. The boards are fabricated by a “board house”, then the parts are put on by a contract manufacturer (CM).
If you are looking for a prototype fabricator, I’ve used Advanced Circuits many times. They do a good job, and have good tools for quoting. Check out their specs and stick with the standard specs to save money. For production fabrication, I let my CM handle it.
I’ve never used a prototype CM, although I’ve done prototypes at a regular CM. There is usually a CM in most decent sized cities in the USA, it helps to work with someone local. If you can’t find one locally, and you’re in the USA, check out Sanmina or Sparton. I’ve worked with both. But for that level of service I’ve never paid less than $3000. At a smaller, local CM I have been under $2000 for simple boards.
PCBs don’t get cheap until you’re buying them by the hundreds and thousands.