Rough Cost to build my first tear Drop.

Hello everybody Im new here and love the site! So im jumping in on my first build and had a few questions. I have my trailer already That was going to be for quads but I found the one i was going to buy for my wife was needing alot of work so I said forget it. So Now I have this great trailer and now want to build a tear drop! I like the Trailer for Two as do many people on here
So what do you think in a rough estimate of building materials, Just the wood im talking about. How much plywood, Frame Rails things like that. I have priced the skin and the interior that I want but will come with time. I have good skills in building just about anything so im confident in that. I just need to wrap my head around a target price.
Thanks for your help!!
Jason

Thanks for your help!!
Jason