You won't economize much more than using Bingham. Like Roy says, you can get in touch with Troy and he can provide you with what you need to build but I'm not sure what he might be able to offer in terms of instructions.
Don't get me wrong, I love Troy's stuff and he is a sponsor here while Bingham is not. I will be placing several orders with him in the next few months. BUT, I'm through the learning curve and know exactly what is needed from the supplier.
If I'm wrong about this, Troy, please jump down my throat and set me straight!
You don't need all the stuff that Bingham offers the first time builder. You don't need a hot box. You don't need a pressure hose form. You can build a straight limbed Bingham long bow on a 2 x 8 form using the rubber band method.
When you take it down to the minimum requirements, you can do the whole project for less than $175.