Well, for <$100 you’re probably looking at a very basic entry-level PalmOs based model (Say a Zire21 for $99, or a refurbished Palm IIIxe for around $70). Built-in Bluetooth or WiFi is likely right out, that’s more like $300. I wouldn’t recommend trying to squeeze into a 2MB model, but 8MB is livable.
As well as starting at a lower price, palmOs devices have more freeware/shareware programs available. They all come in with grafiti, a basic calculator, and scheduling (calendar) applications. I’m not sure what you want out of a “word processor”, text editing on pretty much any PDA is a tough assignment, although you can get foldable, close-to-full-size keyboards to help things out. PalmOs comes with a simple text editor that’s useful for writing short notes, however.
If you want, say, Ms-Word compatibility, you’d need something like Documents To Go, which syncs between a word document on your computer and a version of it that’s compressed and viewable on the pda screen. Don’t know how well it runs on a lower-end PDA, though.
There’s a ton of games availabe, freeware, shareware, and commercial. But you won’t have a color screen at that price.