bow fishing bow.

All depends on if you are just going to shoot a couple times or if you plan to get pretty serious about it. Personally I'm very serious about killed barrels full as often as possible. Any garage sale bow will indeed work. IMHO if you plan to kill alot of carp I would go to scheels and bow the hoyt Ruckus. Its a great little bow adjustable for many lengths in just seconds incase somebody you know wants to try it. Many say why buy a brand new bow to shoot carp??????? Beacause thay are only $269 and its something i trust. If you go a lot you will end up dry firing a time or two. I dry fired mine two or three times this year because of cracked nocks. Just depends how serious your getting. BEST of luck! WARNING-Its very addicting!

is it desirable to have no let off or little let off? I read this and don't quite see the advantage but I've never done it.

Also, do you use sights or not?

I have a fred bear odysse 2, parker buckshot, and they both work awesome. The buckshot put down about 125 carp last season. The letoff thing is not a big, deal, i prefer letoff, but for quick shooting, less letoff is suppose to help.
I think the biggest thing is being able to shot an arrow slow enough. I think a 40lb or less bow is all i would want to use. any more then that, and it gets ugly when something goes wrong.
I think the mission craze would be a good bowfishing bow for $270.
The one thing i am going to recommend is an AMS bowfishing system. It makes the whole thing fun.

Oneidas are kind of the Cadillac of bowfishing bows. They make an Osprey that is pretty much the cat's meow when it comes to shooting fish. But they certainly aren't cheap.
However, you can find one of the older Oneida models for fairly reasonably priced. My bowfishing bow is an Oneida Eagle that I bought used from the Scheels in Grand Forks for 75 bucks. That's probably on the low end, but you get the idea.
It's a slippery slope, though: once you start shooting Oneidas, nothing else will do...

Really any bow will work, I use let off just because thats all ive ever used... The hoyt ruckus, also new at scheels for $260. And no sight! Trust me here all a sight will do is slow you down!