Sure it's easy to DIY something for little to no cost using picture frames or whatever. I've contacted printed with a sandwich of heavy glass and foam board, clamped with some strong binder clips from Staples. Total cost about $10.
But just like any tool, when you have a nice one it's a pleasure to use and of course it does the job well. I don't have the woodworking skills to come anywhere near that point so I'm happy to buy one from someone who does.