All of these guys have given you great advice. take my advice with a grain of salt... gaining practical knowledge on a cheap medium such as a board is soooo valuable. Learning the general process of forming the bow (stock removal, shaping, and general "theory" of a bows shape), forming good fades (the transition from the handle to the bow limb), tillering (impatience in this step can ruin a bow), cutting the string grooves, and finishing the bow is very important. I recommend running through the process a couple times before working with anything expensive. Red oak is a cheapish board wood that can make a good bow, and is a good place to start. Theres also hickory and white oak at most lowes and menards. gluing a handle isnt all too hard, and it can look very pretty in the end, or you can make a "bend through the handle bow" if you so please.
If youre really set on using a stave, another cheapish way to get into it is with a sapling bow! a 2-3" diameter sapling can make a great bow. Aim for about three inches, as it gives you more material to work with. it think it will dry out a little faster too(?). The bowmaking process can be a little different with a sapling compared to a full stave depending on a couple factors, but you'll learn as you go.
TLDR All this is just to say, just start building, ask questions, and be patient with yourself and the process. try to fill the waiting time with smaller projects while you get your hands on you're stave. theres always another board out there to use, always another tree that will give you a good stave.
Del's website has a lot of really good information and thats where I learned! These guys have a wealth of knowledge. ask any question you have. anyways, thats my two cents... im not the most experienced but I hope this added to the convo!
Good luck! can't wait to see you're projects!
p.s. good tools really make a difference... the three most important for me is a drawknife, farriers rasp, and a cabinet scraper. If I only had these three tools I feel like I could get through most of the process and make a pretty dang good bow.