A commission is a huge honour for me and each one is unique, but as a ballpark, prices start from around £600 for a single person portrait in oils that is around A4 size. This will increase with size / complexity and number of people (or animals!) in the painting. I am always very happy to discuss requirements with you.
The way I like to work is to talk to you about the commission beforehand in depth, then make a plan of how the portrait will look and then visit the subject to set up and photograph the portrait as we see it. I will then work from these photographs to produce the painting.
Timing varies a lot, due to the use of oil paint as the medium, but commissions take between 2 and 6 months. A deadline can be agreed beforehand if needed, and I can tailor my working methods to fit as necessary.