Popcultcha has Zartan for 40 bucks, but you've gotta buy some other stuff to make it worthwhile with the free shipping -
https://www.popcultcha.com.au/g-i-jo...on-figure.html
With that said I've used them a number of times and always found their service decent.
Other than that I tend to use BBTS, but I think Cobra Trooper is very difficult to find and even then at high prices. Cobra Infantry would be easier to get a hold of, however not sure what the stock situation is like.
And just found out Classified Major Bludd is another Cobra Island US Target exclusive, the folks at Hasbro must not want collectors buying their stuff. I'm interested in these Classified figures because they look great, and on the whole I've found them to be better than Marvel Legends. And I'm not even a Joe fan - my knowledge of this franchise is close to zero.