Wow kids.woot has this Hex Bug set for only $19.99 (plus $5 shipping) today!
2 HEXBUG nano Battery Powered Robots (random colors) 4 Easy Connect Habitat Hex Cells 12 Easy Connect Straight Bridges 16 Easy Connect Curved Bridges
Go here to kids.woot to check it out.
I checked Amazon prices and this seems like a pretty good deal. Would make a great gift!