I got a complete Barrage for $20. The only thing was his snout thing was broken off. Easily repaired once he came home. He came with his sword and gun, both in great shape. Awesome display piece. The other deluxe Insecticons are on my short list of g1 TFs yet to be aquired.
I won all four from the same seller for around 160 bucks, all loose but dead mint and with all the original weapons and stickers. I was damn lucky since each of them was in a separate auction listing.
I've never noticed any stress marks. They shouldn't as they were rarely transformed, never played with and either displayed or stored. But, to be sure do they usually exhibit stress issues?
Legs on Barrage and Ranksack are prone to stress and breakage, on Roadbuster, the green plastic that attaches to the brown piece that holds the arms are known to stress from transforming him.
As mentioned before, the wings on Ransack and Venom often have stress marks and many snap off. I've seen fewer legs missing, but, yeah, Venom's have a tendency to break off as does the upper region of Barrage's horn. Of course, maybe that's just the ones I've come across.