that I have now, my audiologist allowed me to make payments over a year. That was still expensive, since they cost $1800 each, or $300/month, but if you can get such a payment plan for the $500 ones, and perhaps can find some government or charitable group to help with the cost, that might be doable.
Perhaps, if necessary, buy one aid one year, and one aid the next, to keep monthly costs lower. On a very limited income, even $42/month would be hard, of course, but if you have a government agency or charitable group that would help out--or even relatives who might chip in a few bucks each month--it could work. I have done that for a friend who needed aids. I just chipped in $20/month to help her make her payments during the year she paid them off. She had friends and relatives helping, too--some if whom could afford to give only $5/month, but it all added up to cover most of the cost.
Also consider setting up a Go Fund Me page and putting the link and explanation here on DU. I bet people would help. I would make a donation, though I can't afford to make large ones. But if a lot of DUers chipped in $10, $20, or even $5 each, you could probably get the aids. If you do that, ask for the $2400 for the two better aids. The cheap ones will help a lot, of course, but the costlier ones will work WAY better. Also, your hearing loss is probably progressive, so the cheap ones might not help after a couple of years. My first aids (analog ones) were $750 each, but by 2010, they didn't help at all any more, so I had to buy the expensive digital ones. I couldn't afford them, so I saved for 3 years before I finally got them.
The ones I have now can be boosted, whereas my first ones had reached their limit of possible amplification.
Do consider setting up a Go Fund Me page. I want to make a donation, and I bet many other DUers would, too!