I've got two new Firestone tires (12.4 X 28) and tubes on the rear of my 8N and one new China made and one older Firestone 12.4 X 28 on the rear of my Jubilee. Both rear rims are new loop rims. Some day I hope to repair both of the hat rims I took off the Jubilee, but until then, I see no problem in running unmatched tires or rims on my tractors. Afterall, I can only see one side at a time. ;>)
$1K for two good tires on good rims seems reasonable, but I'd offer less and go from there.