As far as arrow guns(crossbows) being a ton of money, they are new.
But they can be found easily if you're savvy. My Parker Terminator with a red dot site, 24 bolts, quiver, and case cost me 200$ from a guy on craigslist. Shoots great.
The crossbow doesn't really extend the archers range imo. I shoot my bow accurately enough to kill deer out to 50 yards, I only make shots on live deer at 40 though.
The crossbow will go out to 50, but I'd only take it to 40.
The stalk is still the same.
The final shot and kill is just more accurate and sure.
I've got my meat in the freezer now, so I'll be taking out the compound and recurve soon. My goal is to get one with the crossbow, one with the compound, and one with a recurve this year.
A mans gotta have goals!
"Love is when you feel the same way about a person as you do about your motorcycle."
~Hunter S. Thompson