@charliespet - I think people here understand that sometimes finances are tight and medical care for your pet can be costly. I think most people here would also do anything they could to come up with the money, if it meant the animal would become healthy again.
If you get to a point where the medical is too costly, consider rehoming your pet rather than having them euthanized. Someone who has the means to make sure the animal gets the medical care it needs would be the more humane option if the animal has any fighting chance at survival.
Of course, if quality of life comes into play and the risks/poor quality of life, outweigh the medical options then euthanasia is a humane option.
I think where people are having a problem with what you are saying is that it sounds like you have a dollar amount in mind that is your monetary ceiling for treatment and if medical care were to exceed that, then you would opt for euthanization.
Shammy, the first pig I ever owned, developed a tumor on the side of his face. He didn't seem too bothered by it, he was eating/drinking normally, very active, normal pig. His quality of life was not being affected by the tumor but it was a relatively large tumor (about the size of a golf ball)which put weight on the side of his face and pulled his eye socket down. Shammy was a senior pig at the time (5 yrs) but was still full of life so he was not letting the tumor get in his way.
So after talking to the vet about options, knowing that his quality of life was still good, I opted to go ahead with the surgery to remove the tumor. It was expensive, for sure, about $500 but to me, it was worth it so he could continue his life not weighed down by the tumor. Incidentally, it was determined to be a simply a lipoma (fatty tumor and benign).
So in any situation like this, you have to weigh the options. If quality of life will be improved by treatment, then as a responsible pet owner, you would need to make sure that it happened. If it's too expensive for you to possibly consider, then rehoming the animal to someone who is able to provide the appropriate care.
Euthanasia is not an option for a healthy animal that simply has become to financially burdensome. It also is not your only option if medical treatment is too expensive.
Now, when you said, "not with expensive chemicals and syringes", I cringe to think about what you would consider a "humane" alternative.