The value varies depending on condition. A heavily used board or one with a missing piece might go for $20. A board in excellent condition maybe $40-50
That depends on when the board game was produced. Any board game that came out during the height of Beatlemania, in mint condition, probably has collector value. More recent board games (Trivial...
Not much...10 bucks on eBay.
It depends on if it's the 80's version which isn't worth much or the 90's version which came with the 4 PVC figures in it. The one with the figures is worth more because...