135 pieces at $19.99 is a tough sell even in 2018 — this tiny Technic buggy doesn't have the build depth or shelf presence to justify the ask.
The parts alone are worth about 58% of the street price — the basis for this F price read.
OverpricedYou're paying well above the parts' value — $12 of parts for a $21 price.
WHACK! is one of those Technic sets that exists more as a price-point filler than a genuine build experience. The buggy form is familiar to the point of anonymity — nothing in the construction surprises, and the finished model is small enough to get lost on any shelf. At $19.99 for 135 pieces, the value math was never going to work out, and the play pattern is limited even by small-Technic standards. There's no standout function, no clever mechanism, nothing that makes a builder stop and think. The D overall says it all: this is a set that was easy to skip at launch and easier to forget after.
This grade blends these community reviews with set facts and market pricing, and updates as new reviews come in.