Every published rate on this site is a starting point: one image, standard complexity, in a normal turnaround. The number you are actually quoted moves from there, and it is worth knowing which direction each factor pushes.
Edge difficulty
This is the biggest lever. A boxed product against seamless white is a clean path. Hair, fur, mesh, chain, glass, transparent packaging and anything with a soft or broken edge need masking rather than a path, and masking takes several times longer.
Volume
Rates come down as the batch grows, because the expensive part of a job is agreeing the spec, not executing it. Once a style guide exists for your account, the hundredth image costs less to produce than the first. Recurring accounts almost always settle below the published rate.
Consistency requirements
A set that has to match an existing catalogue exactly costs more than a set judged on its own. So does anything held to a colour reference across multiple shoots and lighting setups.
Turnaround
Standard delivery is 24 to 48 hours. A rush slot inside that window is priced for the capacity it reserves, not for the work itself. Booked ahead, peaks cost nothing extra.
The way to get a real number
Send ten representative files — not the ten easiest. A quote against your actual edge difficulty is accurate; a quote against a description is a guess, and guesses move in the wrong direction once the real files arrive.