I only pay for shows on horses that I own (which I 'get back' when I sell the horse) or horses that I show for my own personal benefit. The rest I get paid to show, which is always great. I had a project I really wanted to show and probably spent about $4000 on him. (I did about 10-15 shows this year?) Fortunately that's all tax deductible for me!
I think I usually pay ~$100 in entry fees per local show (just a day, sometimes two). Our clients pay about double that once you add in hauling, day care, schooling, eq and medal classes (don't do those!), etc.
I pay $400-500 in entry fees per rated show (more if I do jumpers, darn those nominating fees!) + hotel. Which is about another $100. I think our clients pay, more then double once you add everything in there. Double THAT if it's a longer haul.
Yeah, shows are expensive!