K’NEX 750 Piece Ultimatebuilder’s Case Building Kit – Link

You can currently snag this from Amazon for its lowest ever at only $31.39 shipped!

• 750-PIECE PACK – This Ultimate Builder’s Case contains 750 classic pieces in bright colors and with sturdy plastic construction. The package includes many different rods and connectors to let builders create extravagant designs!
• CREATE 3D CONSTRUCTIONS – Encourage your child to bring his dream design to life by building three-dimensional models. Whether he’s creating a cool vehicle or a pirate ship, this set allows a multitude of 3D configurations.
• PORTABLE STORAGE CASE – Allow your child to play and learn wherever you are with this building set. It comes with a sturdy case inspired by the design of the original case from the early 1990s.
• FULL-COLOR INSTRUCTIONS – Encourage your child to build and create with the 25th Anniversary Ultimate Builder’s Case. This set comes with color-coded, easy-to-follow instructions that will teach your child to craft 50 models of varying size and difficulty.
• STEAMagination™ – It’s the connection of STEAM (science, technology, engineering, arts & math) with a child’s natural curiosity and creativity and it powers the fun of each and every K’NEX® building set.  Building with K’NEX puts children on a path towards a fundamental understanding of STEAM/STEM subjects.

K’NEX 100 Model Building Set – 863 Pieces – Link

Amazon has this currently marked down to only $25.99 w/ free shipping!

• CLASSIC PIECES – This set comes with 863 classic K’NEX rods and connectors. These pieces can be attached to one another in different ways. It allows your children to create a multitude of shapes, figures, and structures with ease. The snap fit pieces stick together securely and can be easily reassembled into other creations
• REAL MOVING PARTS – Unlike other building toys, K’NEX allows kids to create unique models that actually move. Kids can make interactive toys using K’NEX parts whether its wheels, rotors, wings, and tracks. Making rolling cars, working amusement park rides or a transforming animal isn’t just a dream when you have this 100 Model Building Set!
• VERSATILE – This building set includes an instructional booklet, which shows builders how to create 100 unique models with its helpful illustrations. This toy is ideal for boys and girls aged 7+ and up, as they can make anything that their minds can come up with. Foster your kids’ imagination and creativity with K’NEX. See your youngsters build a blimp, ambulance, or even the Eiffel Tower!