So what do you guys feel is the worth of some of the more popular army builders from the origianl line? Like Viper v1, BAT v1, Cobra Soldier/Trooper, CGs, Snow Serpent v1, etc.? Thanks.

I refuse to paid these prices... But here's the going rate (best I can remember)

These prices are for complete and mint figures...

Vipers $20 - $25
Cobra Officers/Soliders $20 - $25
Bat $15 - $20
Snow Serpent $10 - $15
Tele Vipers $5 - $10
Eels $10 - $15
CG's $20 - $25

Personally I think a complete v1 viper 20$ tops, and a bat 20-25$...

GBPackrat's prices seem consistent with ebay (for complete figs) although Eels and Snow Serpents may even go into the $20 range complete as they have harder to find accessories than say a Cobra Soldier or Viper.
These guys can be had a lot cheaper, however, if you are patient and either buy in lots or wait for a cheaper seller. I have bought 3 Vipers for $10 each from guys at shows (actually, Krymsyngard) and 1 at a yardsale, and several more for cheaper either at a store I go to or in lots. Pretty much same deal with all the other army builders.