About 3 years ago, I bought a 24 inch viewsonic VP2468 for $207 from Best buy and a Raspberry Pi Zero W (and installed dakboard) for $35 from Amazon.
It looks like this: http://lishutterbug.com/t/frame.jpg
It's "only" 1080p, but the reality is it's wall mounted so you don't get that close to it. It's more than sufficient in resolution. Color accuracy and good viewing angles are far more important. It's one of the best things I've ever bought. At the time, I had to convince the wife it wouldn't look cheesy.
If it ever broke, I'd go bigger for sure. I looked at some of the other recommendations and $600 for a 32 inch is fairly reasonable, since it's pretty idiotproof. If you buy a monitor you want one with a very clean outside look (no buttons, ideally no logo) so it kinda looks like a picture frame.
I need to set up another frame for a relative's place, not sure what I'm going to get. Getting a real big one and going wall mount is 100% the way to go, imho.
my web page is sort of my photo blog.
I will write a comment if there's a supplemental thought/memory I want to remember with the picture (that I'll forget years later). Also because people scan pictures so fast, I will also usually write a comment if there's something interesting and not obvious in the picture at first glance.