Amazon has the Mega Bloks Cat Cement Mixer for $9.99 with free shipping for Prime members or on $25+. Includes truck, mixer and 8 building blocks, build right onto the mixer's cab or lid, perfect for little hands. Has excellent Amazon Reviews.
Walmart sells it for the same price.
Ends 10/1. Amazon has the Meigo 117-Piece STEM Building Set for $36 - $18 off with coupon 50KEDURE = $18 with free shipping. Features 114 blocks, 2 ratchets, and 1 plastic power drill, instructions for building several different shapes, lead, BPA, and pthalate-free.
Has good Amazon Reviews.