There are services which would charge for hosting, and provide a general purpose UI for a database backend. You could check out Wordpress' hosted service or Adobe's Business Catalyst, maybe, but if you're looking for a turnkey solution which won't require any real effort to pull off, you're not going to find it. Unless you want what basically amounts to a blog and some static pages, someone's going to have to build it from some value of "scratch."
Thanks. I'm a little surprised by the answers in this thread. I guess I run into what I'm kinda looking for so much I thought that it wouldn't be a big deal to find a turnkey solution. Everyday I use mobile apps that show me where things nearby are and how far away and allow me to search product listings. I dunno, I guess I thought it would be a thing I could set up in 30 minutes like Shopify because it seems so ubiquitous. The fact that I couldn't find a solution after Googling should have been a hint, but I figured it was just hiding and HN would know. Thanks again.
Simplicity isn't easy. Chances are if your idea hasn't already been implemented elsewhere, and it's any good, then it can't be whipped up in half an hour. Good luck.