It is a chalenge to start in this bussines. I have 9 eyars of experience in the field, taught photography and a little of photoshop most of the time. Let's start by aswering some question!
It comes down to: What do you need. If you only need some basic exposure/color correction, it can be done in a minute and cost cents. If you need heavy manipulation, it can take a day and cost $100, for each photo. The number os photos, price and turn around time needs to be agreed for each project.
The basic, lightning faz basic correction that I offer includes: Exposure, contrast, level balance, color correction, crop & leveling and chromatic aberration correction. All of that for $1 a photo! For skin cleaning and a little more manipulation, $2 a photo.
The turn around time varies by the demand and number of photos, but in a day I can edit 100 photos
I hope to have answered your questions! And if you need lessons or general photography advice, contact me