Stargate is a good game - arguably the best of the Gottlieb System 3 games.
In nice condition and in good working order usually about a 1400-1700 game.
Two common problem areas I have seen with Stargate:
1. Top side of playfield - a lot of bubbling and discoloration of the mylar, which covers most of the playfield. This can be fixed by complete removal of the mylar but it is a royal PITA.
2. Bottom side of the playfield - I have seen more than one Stargate with really bad corrosion of the wiring, connectors, light boards, and especially light sockets over the entire bottom of the playfield, not directly attributable to bad storage conditions
Inspect thoroughly.
RussMyers