Compared to other types of bowhunting, bowfishing is cheap and requires very little gear. You can get even a top-end bow and bowfishing reel for less than $400. If you're particularly thrifty, you can just buy a used bow at a pawn shop and build your own reel out of a sports drink bottle. My drink flavor of choice is yellow Gatorade, but you could probably get by with a different color, or perhaps even an off-brand flavor. You do need a fiberglass fish arrow, some bowfishing line, and a few pieces of hardware, and you need to ensure that the bow you're using has a stabilizer port.