Gashapon, gachapon, gacha gacha, ガチャガチャ — same machines, different spelling.
Anime and game figures, keychains, charms and more — 19,000 collectible sets back to 2000. Search in English: type “Attack on Titan”, find 進撃の巨人. And when you find one you love, having it sent from Japan is simple.
They all name the same machine. The word is a noise — the gasha of the crank turning and the pon of the capsule dropping — so it was never spelled one way to begin with. Bandai registered ガシャポン (gashapon), ガチャポン (gachapon) and ガチャガチャ (gachagacha); Takara Tomy Arts registered ガチャ (gacha) for its own. Written in Latin letters it drifts further — gashappon, gachappon, gacha-gacha, gasha pon, and gashagasha, which is what this site is called.
The generic term, and the one the archive is organised around, is capsule toys — カプセルトイ. A few hundred yen, one turn of the handle, one capsule, contents at random. Every set here is listed under the name its maker printed on the box, which is why the names on this page are Japanese and the search takes English.