My vet does the service free of charge. More should. Better than shooting a loyal family pet.
Our vet has also let us know that this is his policy, simply because he said that he has seen people put off euthanizing an animal for too long, several times because they can't bring themselves to shoot it and don't have the money to have it put down humanely. He will even get rid of the carcass.
One of my least favorite tasks around the farm is taking care of old cows. I've mentioned before that I am a really bad farmer, because I treat most of my cows as pets. We tend to keep the old girls around far after they need to be kept. I am usually of the opinion that if the cow has been good and had pushed out 10 to 12 calves, I'll let them ride out their last few years in peace. It only costs me a little hay and a little medicine, and alot of time I'll end up getting one more calf out of them that basically makes more money than I would have gotten had I sold an old cow. I know that from a business perspective, I should sell them. But I also get to see them enjoying the pretty days and chewing their cud, and basically doing nothing. The real downside is that eventually they will get sick or injured, and usually can't stand up anymore. At that point, I'll have to do my duty and put them down. It's just part and parcel of farm living. I don't like it, but I do get the satisfaction of knowing that they had more good days than bad, and in the end I did my part to limit their suffering.