I would say the entry point is less than 100$(nikon coolpix) plus making photographs. Scanning takes so much time. Good ones uses 600$ canon or nikon(you can share use a friend digital camera)

Today people can share(or rent) relatively expensive scanners(1000$) with ultrafast feeders(any book in less than a minute) it they don't care about destroying the original book(just "guillotine them"). I had so many books that I did it with hundreds of them, my entire collection will be digital some day.

It hurt the first time I did it, but there are so many advantages(you can move with all your books, no weight, search funtion, indexing, digital notes)