What's a decent "cheap" (I'm on Disability) camera that
will upload onto the computer ?

There are lots of them! But it depends on how you define cheap. If you're looking for under $25 and in new (not used or refurbished condition) your choices are limited, but you can still find a name brand (Kodak, HP, Polaroid) camera, especially if you're not worried about a garish color (like pink). 

Here's a link to a search filtered down to new name-brand cameras on Amazon for $25 or less (although there are some showing up as Used even though I chose new in the search string because the seller is trying to be sneaky – so be careful). 

I'm not a camera guy, so I can only give you basic advice based on what I've used in the past. In my experience 3-5 mega pixels is plenty of image quality to post on the web. In fact, 1 mega pixel is enough, but finding a 1mp camera nowadays with good optics would be hard. But I've seen 10 year old sony digital cameras that are 1.x mp that take excellent pictures! But these were top-of-the-line cameras in their day with excellent optics. To get a decent camera today that's new, you'd probably have to buy a 3+mp camera. But bigger isn't better if all you want is pictures for the web. If you splurge on a 10mp camera you'll just have to edit the images to make them smaller before you upload them. Ideally you want your images to be less than 1 megabite in size when you upload them. A truly optimized image for the web can be as small as 2-300k (or in some cases even smaller) and still look excellent. 

Just for clarification. A 3mp cameral will give you a 3x5 image at roughly 300dpi (color printer quality). But since your average computer monitor displays 72dpi, this is 4x more resolution than the monitor can handle (so it's just wasted picture quality). Not to mention that most images don't need to be 3x5" to be effective. 

Again, I'm not a camera guy so someone please jump in if I'm way out in left field. 

Another thing I learned the hard way is try to stay away from a camera with a proprietary battery. They are expensive and don't have a long life span. I've had two digital cameras. One I liked (a sony) and one I've hated (an HP) and the main difference was the HP had a funky battery while the sony took AA's. So my HP was always dead when I needed it. Well, my Sony was also usually dead when I needed it, but the difference was I could pop two cheap AA's in the sony and take the needed photos. I had to wait to charge the HP (you couldn't use the camera while it was charging). If you think you want a proprietary battery because it's rechargeable, get rechargeable AA's instead. 

Now, after that lengthy dissertation on a subject I'm far from an expert on … I give you this advise.

If you have a newer cell phone that can take pictures you should try that first. You'd be surprised at the picture quality of the phones these days. My iPhone takes HD video (720p) and excellent photos. Any newer "smart phone" should take pictures that are just fine for the web. So if you have a newer phone, or you're ready to upgrade to a new cell phone it might make more sense to invest $0-100 (some phones are free with a new contract) into a new cell phone and kill two birds with one stone. Just a thought.