I spent a little over $1,200 on my 2 horses last year. We kept them both on our own property, and the ferrier and hay we got cheap, so we did not spend that much.
I do know that some people spend well over $10,000 on horses per year. Since I moved though, I get board and lessons free so for 2010 I estimate to spend $1,800, instead of $8,805.
Horses are EXPENSIVE!!!