The service call is free and the price is agreed before anything is touched. Published ranges by appliance type are on the way to this page.
Most appliance repair sites answer the cost question with "call for a quote", which is a way of not answering it. We would rather publish real ranges by appliance type, and that table is being finalised. It will appear here rather than in a phone script.
Three things, in this order. Whether the failed part is mechanical or electronic, since a fan motor and a control board are different worlds. Whether the unit is freestanding or built in, because access on a built-in column can take longer than the repair. And whether the part is current or has to be sourced for a discontinued model.
What does not move the number: the day of the week. Sunday is priced the same as Tuesday.