Most folks don't buy wood for turning unless it's exotics or burls that are not available locally--if they can help it, at least! The best sources for turning stock are in your back yard, in the woods, along the road, from local tree trimmers, etc. Turning is one of those activities that you can use material perfectly unsuitable for other forms of woodworking, too...shorts, chunks of crotch wood, etc.
That said, gluing up is not a problem as long as you don't mind the look of the glue lines! But even that is manageable if you combine species for contrast and use the lines between the layers as part of your final design. Use regular woodworking glue or epoxy and clamp them well until cured.