I'm new at both beekeeping and woodwork, so please bear that in mind.
To make some medium bodies I purchased three 1" x 8" x 8' boards, at a cost of about $9 each.
Despite them being sold as premium grade I would put them in the firewood class, because that's about all they could be used for. Full of knots and about as straight as a dogs back leg. I did manage to make some usable bodies of of them though, but due to the waste from trimming them from 7 1/2" to 6 5/8" I looked at alternatives.
My local big box had a good selection of 1" x 4" x 8' boards with very few knots at about $2 each.
Cut the boards to length plus an extra 1" for trimming. Ran the edge of two boards through my budget router table with a 1/4" slot cutting bit set at 3/8" deep. Cut a strip of 1/4" lujan plywood to a width of 5/8" and used it as a spline. Used a quality exterior glue, clamped it up.
When dry trued it up and trimmed to length to give a 7" wide board for less than half the price of a 1" x 8"
Add a third board and you will get a width of 10 1/2", perfect for a deep.
http://www.woodworking.com/ww/Article/Adding-Biscuits-and-Splines-7590.aspx