Asking "what's an ebook cost" is too wide a scope. It's like asking "what's a physical item cost?" It's unsurprising to find a large range. When you narrow the search, you find established values. Digitized classics go for $0.99. Novels are about $9. Textbooks are similar to their dead-tree counterparts, at $60+. Serious reference works can be thousands.
Run of the mill technical books clock in in the $20 to $40 range. I'd aim for that, and go high or low within there. And as a new author covering a widely-known process like agile, (opposed to the landmark work on a popular language), low would probably be best.
How much the book saves a business is immaterial. If it's a truly academic, novel work, you might justify a premium. As it is, you're hardly the only person writing about agile.
Run of the mill technical books clock in in the $20 to $40 range. I'd aim for that, and go high or low within there. And as a new author covering a widely-known process like agile, (opposed to the landmark work on a popular language), low would probably be best.
How much the book saves a business is immaterial. If it's a truly academic, novel work, you might justify a premium. As it is, you're hardly the only person writing about agile.