I think the only time to play Bonk 3 is when you have 2 people around, in which case it is great. If not, I stick with the original (though others will argue for Revenge).
You should pick up 1 and 2 while you are at it, since they can easily be found in the $10 range if you don't mind loose games.
As for selling the game, you could probably get $150 for a loosie on ebay, but then when the ebay fees are added and you ship the thing (assuming you pack it right), you will make $20. Unless you are incredibly strapped for cash, just be happy you found the game at a reasonable price.