This happened to my wife at a small PR firm. She told them she doesn't have a laptop (she didn't really have a functional one) and they just bought her a personal one as a 'signing bonus' and they have her bring it in.

It's a bit unusual, it's a yellow flag for sure, but it depends on how desperate you are for a job. If that's the worst thing about the company, it's not so bad, I've definitely worked for worse.

I'd tell them "i don't have a laptop, just a desktop" and see what they say? If they seem like they're going to not hire you for that, I agree with what other folks said, buy a cheap chromebook.