Yeah I don't know how that is possible either. ITs probably a copy of the Starweb Play by Mail rules - not the same thing. I spoke to Rick Loomis and he doesn't even know if he has a copy of the WEB RPG rules, so only Mike Stackpole would have it..
a. Empire Builder. Your people believe in manifest destiny. It is your goal to control as much of the universe as possible. You get one point per turn for each 10 population controlled by you (except for converted population; see "Apostles"). You get 1 point per turn for each Industry controlled by you. and 1 point per turn for each RMP (Raw Material Production) controlled by you. (In other--words, a planet with 4 Industry, which produces 6 RM per turn, and has 10 population will gain you 11 points per turn.)
b. The Merchant. You are interested only in trade. You get 8 points for each RM you unload on some other player's planet. You also get points for unloading Consumer Goods (CG) On your own worlds (Consumer Goods are created merely by unloading RMs and declaring that they are CG's). The first time CG are unloaded on a particular world, you get 10 points. The second time you get 8 points. The third time it is 5. The fourth time it is 3. After that it is 1 point. (You get points for unloading 1 CG. If you unload more than 1 CG at the same time on the same planet, you do not get any extra points.)
c. The Pirate. You are interested in plunder. You get points for plundering worlds. (You plunder I world merely by owning it and declaring that you are plundering it.) The first time a particular world is plundered. you get 50 points. The second time it is 40 points, then 30, 20, and 10. Thereafter it is 10 points each time. A world can only be plundered once every three turns, and during the 3 subsequent turns, it will not produce RM or increase in population. (If any player other than a pirate plunders a world for instance to keep I pirate from getting points, that player loses 5 points). Pirates also get 3 points per turn for each key that they own.
d. The Artifact Collector. As the richest person on a rich world, your jaded tastes are excited by the idea of owning unique things. On many of the worlds in the system, there are various indestructible artifacts left behind by the ancient race of beings. You get points for each of these you own. (See the section on "Artifacts".)
e. The Berserker. You are a computer in charge of a race of robots. Your prime directive is to kill all life wherever you find it. (You have no idea who gave you that prime directive or why, nor do you ever question it.) You are allowed to make temporary alliances with living beings if it will further your prime directive (i.e. allow you to kill even more beings!). However, your robots and people cannot exist on the same world at the same time. (They kill each other off--one robot kills 2 people and 2 people kill one robot. )You may control worlds with living beings on them, but no other player (except another berserker) can control a world populated by robots. Your robots may ignore the population limits described later in the rules. (You don't care how many people a world will support, since your robots are not people.) You get one point for each population you kill (normal or converted, but not robots) by shooting, by unloading robots on the world, or by destroying the planet. If you destroy a fleet of ships, you get one point per ship. (If you only damage the fleet, you don't get any points.) If you destroy an entire p1anet(!) by dropping a PBB (Planet Buster Bomb) on it, you get 100 points, plus 1 for each population. (If any other player drops a PBB, he loses 50 points.)
f. The Apostle. You are a religious fanatic, and your purpose is to convert the entire galaxy to your particular religion. If some of your converts are on a world, each of them has a 10% chance of converting one normal population to a convert, each turn. If you have a fleet of ships at a world. each of your ships has a 10% chance of converting one normal population to your religion each turn. If at any time, you convert all the population of a world. you gain control of that world. Other players may get rid of your converts by killing them. But you get one point for each one killed (martyrs) and he loses one point for each one he kills (unless he is a berserker, of curse). Or they may get rid of converts by converting them back to normal by unloading consumer goods on them (bribing them with material goods). Each CG has a 20% chance to convert one convert back to normal. Apostles also get 5 points per turn for each planet they control. and 1 point for each 10 converts they control. You lose one point for each shot you fire (you are a pacifist). Once during a game, you may declare a Jihad against anyone player. From then on you no longer get points for martyrs, but you don't lose points when you fire at that one player. and you get 2 points for each of his people you kill.
That's indeed a description more adapted for a management style game than a rpg.
Though it gives ideas for a (quite violent) setting. Mix MSPE with Garen Ewing Trolls in Space (and a set of simple rules for space action like those) and you are set.
Looong ago, I did use Starship Captain from Standard Games and Garen Ewing futuristic weapons (toned down I think) for a small MSPE campaign based on Traveller scenarios. I seem to remember that it was quite fun (and bloody) and it didn't needed many additions to the rules (a few skills mostly, and having read Dune a little before, T&T magic rules were also plundered for a Bene Gesserit like order).
A copy of "WEB: The Starweb Role Playing Game" just sold on Ebay for $100.
A lot named "STARWEB FROM FLYING BUFFALO RARE 1ST ED!!! ROLE PLAYING GAME - 1976 Star Web" (with errata dated 12/76) recently sold on Ebay (Jan 11th, 2016) for $100 plus s/h. If that's the sale the OP referenced, it was a print of PBM rules, not an RPG as the seller lists.
FYI - The seller of this lot left a nice note of feedback to the buyer: an outlaw hobb who has recently [Dec 2015 - Jan 2016] listed multiple Ebay lots (of T&T/FBI materials) claiming they were "purchased from Noble Knight and never used" and "I no longer play RPG's."