Hyperball is an interesting machine.  I think it would go well in a large collection and I reckon kids would love it (point and shoot).  From memory they are based on a Williams System 7, so as long as boards, playfield and shooting assembly are complete, coin door should be easy to find.  If its the lockdown bar/shooter assembly that would be tougher to find.
Complete and working in good condition I think any where between $700 to $1200 max.  If mint maybe $1500.00 to the right collector.  Not heaps of them here.
Parts machine value I think $300 depending on the boards.

Volcano - is one a unique Sys80 game. If its an Aussie delievered (or Euro import), check for wear around the bumpers and as long as the playfield & backglass are good they are an easy fix.  I would suspect there would be serious interest on this game from the Sys80 lovers out there.  Fun System 80 to play.  A quality example of a Volcano I think max $1500.00

Stern Magic - no idea on that one, never had one!