I think I set my limit at $2,000 or $2500, I'm not sure. That was last fall and out West which may make a difference. I ended up paying $1500 for a very solid, and big ('cause I am), trail horse. He is not perfect--but most of his problems can be attributed to me, the inexperienced rider.
As I learn to ride him better, I'm sure he will learn to be ridden better. Actually, it's already happening. And I just started "formal" training which will accelerate the process.
I don't know where you've looked, but we had our best luck on DreamHorse.com. It allowed us a lot of flexibility in our searches--price, search area, characteristics.
There are also a lot of horses around here on CraigsList.com. But that wouldn't be my first choice for finding one--in part because they generally don't list much information about the horse.
But, in the final analysis, how much you pay will depend on how much horse you want and how "finished" you want him/her to be. Speaking from experience, if your husband is new to riding I'd suggest you pay a bit more and avoid the frustrations of having to train a horse and a rider at that same time!
"Don't just feed it! Ride it!" And the People said "AMEN!"