I'm guessing that you are looking for either a free giveaway or deep discount on a tablet or laptop and I do have some other suggestions since I am also disabled (long term) and a senior citizen. I have used computers for many decades now and used to write programs and build my own desktop units, so I still tend to look for something more powerful for myself than most folks really need, but I do my best to be helpful to others who are looking for help in getting something less powerful and something they can deal with easily.
I see in the reply from R. Proffitt that he does mention the Chromebook, but infers that people are not satisfied when they get one. He brings up a very valid point though, you have to be clear - in your own mind and in communicating with others, about what you want your computer to do for you. You mentioned listening to music or reading a book and you could even add in watching movies or TV series and the Chromebook can easily do those things for you. I will tell you that I personally avoided suggesting the Chromebooks because I just found it hard to believe that anyone wanting to go online, would be satisfied with a tablet that they can't actually grow with. However, the better information I started getting from those looking for a tablet/laptop and placing myself in the users shoes, I have honestly been able to see the appeal of such a machine.
My actual career was in law enforcement/investigations so I am one of those dinosaurs who must have the latest and greatest version of WordPerfect Office - the point of that is the space that's needed to install all the programs included in the Office version is just one of the many software packages that I install on my computers. All the programs that I use, plus the data that's created by those programs, can quickly fill up a hard drive, so thinking about using nothing more than a Chromebook is absolutely out of the question for me.
However, I'm strongly considering getting a Chromebook with a decent sized screen to use for nothing more than watching videos online. I'm like you, the only comfortable place is my bed (snuggled up with my service dog, of course) and I have a nice laptop table on wheels from WalMart so that I can move the screen close to me and then push everything away when I want to get out of bed or I'm done with the 'puter.
Check, or ask someone else to check for you, Amazon and see the kind of prices that are available there. If you find that you are able to buy a new or refurbished with warranty, that will resolve the concern that R. Proffitt brought up about support after the machine arrives. I would suggest that you not go for the cheapest you can find, wait a few extra months while you save up more money. As for getting more money into your budget, believe me, I know what a challenge that is, but I also know that it can be done when you set goals and you're willing to make necessary sacrifices. It's been a little over 5 years since I've had a TV and I have not been able to pay for any kind of cable service since I began using service dogs. It's always been a priority to take care of my service dogs first and figure out entertainment later (besides, they add a tremendous amount of entertainment themselves, besides helping to keep me safe). There is so much free entertainment online that I honestly have not missed a TV and there are inexpensive services that you can purchase for even more choice and variety. Although, if you want to use online movie and TV services, you do have to pay for high speed internet service and that's not cheap either, but it's so very worthwhile.
I was just thinking that you might have brought up being unable to sit in your chair because that's where you access your computer from at this time. Here's another thought on an idea that I used before I was able to get my first laptop. I was able to buy, for about $70 from Costco, a really nice, open computer desk (or mini-desk?) on wheels and I used that to be able to use my desktop computer from my bed. If you already have a desktop computer that is adequate for your use, you could try that option. Wow! I just did a quick search of Costco.com and there's nothing reasonably priced there, but when I looked at the best desk shown - I received a notice from Amazon of a better price so I searched Amazon next and here's a nice, rolling desk for under $70
Do remember though that the local Costco warehouse usually offers more and cheaper options that Costco online.
If none of these options will work for you, you might try contacting your local computer repair shops and let them know what you are looking for and the top amount you'd be able to pay. I really advise trying to save up enough to buy something new online, so understand that if you end up with a machine through this method, you really can't complain to anyone if it gives out after 60 days and then you're on your own again. Also, if you belong to any groups - community, veteran, church, etc. you can ask if you can post on a bulletin board or someplace that you need a tablet/laptop and you never know who has been holding on to an older model just because they didn't know what to do with it. It might also be helpful to check Craig's list, just remember that even if you go and see the laptop working just fine, you might get it home and discover that it overheats or has some other problem within the first hour and you have very little recourse for justice there. Same goes for eBay and I really have found very few good deals there in several years.
Whichever way you go - I wish you the best. Having a decent computer is really helpful in our situations and can provide so very much information along with entertainment.