I finally got together some prices on the materials used, so I could get a general estimate on the cost. Its definitely way less than some of the numbers that have come up on here, but in material it is undoubtedly still more expensive than any moped pipe (and probably any 2 stroke pipe) ever made. I'm just going to lay it out as if someone were buying all these materials new. You and I realize that this pipe was made from scrap pieces of material that I am fortunate enough to have access to, but lets pretend somebody actually wanted to buy the materials and make this thing.
The 601 0.032" Inconel sheet was 4'x10' and was purchased for $2,241.32. That puts the price $56 per square foot. If laid out correctly I believe the cones could be made with a 2'x4' sheet.
2'x4' 0.032" 601 Inconel sheet- $448
0.045" wall 7/8" Dia. 625 Inconel stinger tube- $63 a foot
0.028" wall 2" Dia. CP2 Titanium baffle tube- $33 a foot
Machined CP2 Titanium ferrule- $86
6- 3" SuperTrapp Stainless discs- $28
Stainless mounting hardware - $3
Fiberglass baffle packing- $10
Misc. items I don't have an exact price on- conservative guess - $100
0.1" 601 Inconel used for pipe mount tab, 1/4" Inconel for flange, 0.06 601 Inconel used for baffle mount, 0.035" Stainless used for baffle caps.
That puts just the materials price at around $771
Comparatively the materials used in a regular mild steel pipe, say a Doppler, probably total less than $50
Thanks for all the comments and interest. It was a great project, I'll try to get that video of what it sounds like up soon and also post on its performance once spring and riding season is here.