Congratulations, this should be a lot of fun for you. One of the first considerations you must address is what is your bellows extension? That will determine the maximum focal length lens that you can use. Some of the double extension field cameras are limited in the amount of bellows draw that they have.
All of the thoughts that others have shared with you are valid. I would consider the focal length that you normally use on the camera that you now use. (I don't remember the format you have been using). If you commonly use a normal focal length on your present format, you will be most comfortable in the 300 mm range on the 8X10. If you use a mild telephoto now, use something in the 450 mm range on the 8X10 if you have the bellows draw ( 24 inches minimum) to accomodate. If you use wide angle now, then use something in the 210 mm range on your 8X10.
Not all focal length lenses have equivalent covering power (ability to project the image circle and allow for movements). For instance I have a 210 Dagor that covers my 8X10 and a 210 Symmar S that will barely cover 5X7.
If you want inexpensive, then a process lens will work...since you will probably not enlarge the negatives you can stop the lens down and use a lens cap to control the length of exposure. Or you can use a Packard (pneumatic) shutter on those lenses as well. Since you will probably consistantly be working at F45 and smaller, if you use a 125 or 200 speed film such as FP4 or Bergger BPF 200 and rate them at their true speed (64-80) shutter speeds become more lengthy and easier to control without a modern shutter. Good luck and have fun.