Once you start going to larger formats, going wide gets pricey fast. I think the fuji gsw690 models start at like $500. Press cameras are cheaper, but very wide lenses are expensive. To go faster, you can also spring for a roll film back. And your final option is to go pinhole. The cheapest if you build it yourself, and order a nice laser cut pinhole. You can use sheet film, paper, or roll film depending on how you design it, and while designing it you can create one to go as wide as you want.