I just found a SUPER HOT deal at Amazon Canada for this K'NEX Super Mario Cat Mario Building Set. Originally $39.19, the set is being sold for only $8.42 with free shipping from Buy4Less Canada at Amazon. Make sure to click the link "14 new from CDN$ 8.42" OR go to the "Compare Offers on Amazon" bit under the add to cart button.
This is a wicked cool set combining the Super Mario world with K'NEX. You get to build a course inspired by Super Mario 3D Land and you get to build Mario in a Cat Suit as well! The build-able set comes with a Mouse Enemy and a Warp Pipe. There is also a jump disk and launcher as well as a pop-up flag to clear the course.
While I do not often write about marketplace sellers, this appears to ship from the United Kingdom - not China - which is a good sign. I have heard of Buy4Less before and they have very solid ratings: 4.4 stars over the past 12 months (1,837 ratings). Given that they continually get good ratings, I am pretty sure they are selling authentic goods (or people would complain). The same set currently costs $31.58 from Amazon directly.
This is a sweet little deal and that free shipping on just this item is really helpful as well. Grab this before the price changes or it sells out.