Walmart has this K’Nex 521 Piece Value Tub on rollback right now for only $15! You can have it shipped to the store for free or pay to have it shipped to your house.
You can also get the K’nex 521 Piece Value Tub on Amazon for only $15.99. If you have gift certificates to burn or have Amazon Prime, this might be the better way to go.
Regardless of which deal you plan to do, I’d do it soon! Prices can change quickly on both sites!
(Thanks Free Snatcher!)