There are specialists who will appraise Hot Wheel collections. You'd have to check in your area for a specialist. Another way to find out how much your collection is is by seeing how much certain cars go for at auctions.
You can take them to local collectible store to have them appraised. You can have an auction company who sells them appraised. You can appraise them by checking their values on an auction site such as Ebay.
