builder said it was cheaper to spray popcorn on every ceiling than to prime and paint the drywall ceiling.

Paying the extra for no popcorn was in the contract. They accidentally sprayed popcorn anyway. I told the builder (who knew it'd been an important point with me) and he got his crew to scrape it all off. The next time I visited the site, the crew told me it was a messy, dusty, tiresome job to scrape all that popcorn off every ceiling in the house (and this was a crew that was definitely used to messy, dusty, tiresome jobs).

Maybe it was really super-easy and they were pulling my leg, but just make sure of what you're getting into before you sign up for that popcorn-removal job.