Fashion, glamour, product and industrial work tends to be less "inner-based" and more an application of careful craft in response to distinct specifications. Each shoot is unique; locations may be involved; hair/makeup may be involved; special equipment and techniques may be involved; sophisticated advance preparation or art direction may be involved - and so on. It's most appropriate to quote each job individually - based on day or half-day rates for prep and shoot days -- and a time-based rate for Photoshop finishing.
There's always room for flexibility, for finding less costly approaches and for "making a deal." There is never room for compromising quality.
PREP: $500/day -- $300/half-day
SHOOT (includes studio and all equipment): $2,500/day -- $1,500/half-day
FINISH (includes computers, software and disks): $75/hour - but quoted by the job requirements