Yeah, your vehicle is not covered under the used vehicle package they make you buy so you need to get it appraised so the license office knows how much GST to charge on the purchase.
What I did was get 2 appraisals done.
First one was $40 from the local paint shop right accross the street from the MTO office. I was straight up and told the appraiser that I needed a low value to save $$ at the MTO office. He listed the car with a value of $2500 and listed some suggested repairs ( paint, bodywork, tires, ect... ). 15 mins later I was back at the MTO office. Used my existing insurance policy number, Paid the tax on the transfer, and new plates + sticker
Once the car was plated I called Lant Insurance for their Silver Wheel Policy ( $90 year ). They sent an appraiser out a couple days later ( paid him $120 cash IIRC ). He gave the car a thorough appraisal complete with pics and all. He valued the car at $9k full replacement value and sent a copy back to Lant who approved the policy and sent me the slips about 10 days later.