The last taco wagon that I saw in person here in OKC the guy was asking 500. After 3 months on CL he could not sell it. I purchased it for 200. It was blue and red. It was beat to chit, and needed some love n. I spent an additional 300 for bead blast, body work, and paint. I gave it to a family that has 3 mechanics at their home shop. They live in Chickasha OK which is a rural town out in no mans land. They were much appreciative, and the box is getting good use.
If this is for your personal use, I would not pay a dime over 500.