Good Question.
Solar, about $5200 total. This includes wiring and misc hardware. 4 x 100 panels, 3 x 100 Battleborn, Renogy Dcc30S MPPT Alternator charging, Victron IP67 17A 110v charger.
Van build, $12,500, this includes the Solar costs. A lot of the materials (wood wire hardware) were recycled stuff I had already.
I calculated that I had about 1000 man hours designing and building. Building cabinets and walls in a Van (especially a Transit) is a nightmare. Everything is curved, walls ceiling. The cargo area is wider and taller in the back and tapers toward the front. Every piece of wood is custom cut.
If I made another (But I wouldn't) just like it now it would take less then half that.
A local Van Builder her is Frederick MD (OGAVans) charges $43,500 for a similar interior.
Mine is not quite that level of quality, but pretty close.
I submitted an estimate to my insurance company that values the build at $35,000.
So I saved $22,500, for four months of 12 hour days. (not an exaggeration)
I'm a 62 year old retired guy, what else could I be doing in a pandemic ?