8X10 isn't necessarily exponentially more expensive than 4X5. It is more expensive, yes, but with 4X5 you will need a large, heavy, bulky enlarger to get prints larger than 4X5. With 8X10, you can make contact prints with simple equipment.
My first large format camera, not counting an ancient Ansco 3A folder, was 8X10, and I never regretted starting out with the larger size. If you shop carefully, you can get a usable 8X10 camera for about twice the price, or a little less, of a decent 4X5. Also, if you shop carefully, you can get a usable 8X10 lens for a bit less than twice the price of a good 4X5 lens. And you don't have to look for an enlarger.
8X10 film is about 4 times as expensive as 4X5 film, but you can make negatives on printing paper, ortho litho film, and X-ray film at much less cost. X-ray film, especially, is far less costly than 4X5 photographic film.
You can get a used tripod with head that will handle 8X10 for not much more money than a good 4X5 tripod. Old Majestic tripods are considered good for this.
I use an inexpensive contractor's tripod with a large, heavy wooden plank mounted on top that supports the entire bed of my ancient and not very rigid Improved Seneca View. Cheap and ugly, but I have no problems with unsharp negatives due to camera movement.