Certainly looks like scale rot to me and closely resembles all the photos I was able to find in my care and husbandry books for ball pythons. I took in a rescue who was "free" with a similar issue except he was and still is missing sections skin/scales where his well-intentioned but piss-poorly informed previous owner allowed the humidity to get too low, resulting in horrendous sheds that ripped the skin off. That animal, if you elect to take it in, will more than likely always have scars. And if you get it for "free", it won't be, lol! My "free" snake is now in the neighborhood of $300+ with vet visits, stool sample lab workups, treatment for his missing sections of scales, etc; if you're able to make that kind of commitment, financially and otherwise to care for that animal and take on all of the responsibilities with no guarantee that it will pull through, by all means, go for it! Not trying to dissuade you, just make sure you can afford it is all and don't make an emotionally-centered decision without thinking it through as much as possible.
I hear you on the feeling bad for the poor thing and I can't imagine how it feels but if you're not able to commit to caring for it up to and including vet visits if necessary, the next best option might be to have it put down or do it yourself. It definitely has areas of scale rot or look like they are to me; the rest of it's skin is pretty nasty looking as well but I can't tell if that's the photo of if he/she is in blue or if there is something else going on with it. If you decide to go for it, just be prepared for the more than likely lightening of your wallet and/or the potential heartbreak of it not pulling through. Weigh your options is all I'd say and good luck whatever you decide!