This may not apply to the fuse kit, but I am in the same situation with my wing kit. I priced out Van's, Aircraft Spruce, and Wicks. AS is the cheapest on all the bolts/nuts/washers. Wicks or Van's is the best bet for rivets since AS just sells them by the pound. You are probably looking at a couple hundred bucks worth for hardware. If you are missing control system parts (rod ends ect.) it will add up much faster. If you don't have the close-tolerance bolts for the wing attach (part of the wing kit) then add another $150 for those.
If vans can't give you a total price, then just have them shoot you an older inventory list and pull the info from there.
It is a very good idea the get the inventory list anyway. Missing bits of angle and sheetmetal add up real fast - do and inventory of the kit before purchase for your own sake.