Hi, welcome to Just Answer. I'm acuramstr. the blower motor can cause the transistor thermo fuse to blow . honda used to sell them together as a kit on some models. so the blower motor probably caused the transistor to fail. but the shop should have checked the blower motor current draw when they replaced the transistor so you should only be paying for one transistor and the blower motor. the shop should pay for the one that blew out because they were not thorough with the repair.
heres the book time and pricing at $115.00 an hour labor they are not hard to replace .