The Best 12 Campervan Conversion Kits of 2022 for a DIY Van Build. 2021/12/1 · Van Type: Ram Promaster, Kingclima Transit and Ram Promaster City Cargo Van Cost: $5,200-$11,700 What They Offer: Modular interior kits with kitchen and bed system Wayfarer vans is a little different than the other van conversion kits mentioned in this article.