I use a general price per sqm for mono blocks, walls, slabs/concrete and if it's easy and local I'll take a % off and if it's heavy and small I'll add a little on.
Sometimes a job will take me longer but it's not worth dwelling about as over the course of time it pans out.
Pricing... I don't think it's worth sharing this as like window cleaning it can vary from one part of the country to another. Look at folks websites from your area as there'll be some who display this.