It really depends on which ones. Commons, like 10-Yard, Golf, and Baseball, you can get for $3 CIB. For others, like Clu Clu Land and DK Jr. Math, you can expect to pay $75-100+, depending on condition. Some of these are gaining popularity/price due to newly-discovered variations, such as Gyromite, Donkey Kong Jr. and Donkey Kong. Most of the other ones in the middle can range from $10-40, most somewhere in the middle.
-Dain