$17,000 sounds way to high but I guess it depends upon where in the country you live. It this kit wood or metal?
I am having a 24X24 metal building built right now (they are pouring the slab as I type). It has 8'6" side walls. The building (only the roof is insulated), slab and all labor is $6017. The same company offers a 24X30 for $6995 (no insulation) and a 30X40 for 10,995. I live in central Arkansas.