Amazon has LEGO Super Heroes Marvel The Hulkbuster Smash-Up (76104, 375-Pieces) on sale for $18.48 (originally $29.99, savings of 38%). This is the lowest price from Amazon on CCC, free ship with Prime.
Alternatively, Walmart has LEGO Super Heroes Marvel The Hulkbuster Smash-Up (76104, 375-Pieces) on sale for $18.48 as well. Select free store pickup where available, otherwise shipping is free on orders $35+.
Note, availability for in-store pickup may vary by location.