I think that's very wise of you to be willing to try. Our crate cost about 50 dollars (canadian). It shouldn't cost more than 100 for you since Casey isn't a giant or anything. If you search ebay or some other places for used ones, you might be able to find a good deal on one.

About the potty thing, whatever works for you and Casey I guess. Kai goes out when I wake up. Sometimes, at 5am and other times at 2pm. Kai's very reliable in the house. We have a crate for him to eat in and go in if he needs to calm down or something. I've used it to punish him (in a way) by excluding him when he did something really naughty. I've also used it for good things like giving treats and playing with his toys in there. He goes in at his own will now.

Try everything you can before seperating with Casey. I know you said that obedience doesn't really work with you two but maybe try mixing it with some fun? Kai will very rarely 'down' on command but he'll ALWAYS go 'find ashley' or 'find nathan'. I figured that he'd always do the hide and seek thing rather than down because it's more enjoyable. It also calms him down on rainy days when I'd rather not walk outside. When I can't physically exhaust Kai, I mentally exhaust him. Never fails.