Offroad design is listing there Tuff Country springs at 215.00 for 2"3"4" ez ride kits and 225.00 for 2"3"4"6" heavy duty kits, I would suggest heavy duty for a plow truck, I just bought a set of 2-1/2" skyjacker springs for 220.00 and thats without u bolts or bushings, I always have a local spring shop make my u bolts, they have a rolled thread instead of cut like you get with most kits.
Heres there link
http://offroaddesign.com/catalog/TuffCountry.htm