Formatting: save money or go with industry standards?

For those who do their own interior formatting...do you go for slightly smaller text and/or space between lines to cut down page count and cost? Or do you go for larger lettering/spacing even though it will cost more?

Using the format that most matches YA dystopian will add 50+ pages (and around $0.50 extra per book). Basically the difference between 372 pages and 410 pages.