Cell phones have wiped out the lower end of the camera market, so if you want to use something other than a cell phone you'll need to fork out more than $500 for a new digital camera.
For most things, especially things just viewed on the web, you don't need a high resolution camera. On the other hand, I find cell phones far less ergonomic than a well designed camera. I use my point and shoot Nikon P7100 for almost everything, since it's got a decent zoom range, viewfinder, and lots of direct access function buttons. It's not quite pocketable, but close, and I carry it on a belt pouch.
I can certainly see the advantages for someone that wants the features of a real camera, but doesn't want to pay more than $150. There's nothing available new at that price point, so your only options are older used models. The big downsides are batteries and memory cards. The proprietary batteries are the biggest problem of the digital age, since they render so many devices useless when the batteries stop being manufactured. Memory cards are the other big built-in-obsolescence factor. It's so strange to talk about film possibly going away, but many of the batteries and memory cards render older digital cameras completely unusable in less than 10 years.