The one-shot is a perennial mail order vehicle, so called because you market just one item instead of an entire line, and you therefore have one shot in which to sell it.

Thoſe walled garriſons will I ſubdue, And write my ſelfe great Lord of Affrica: So from the Eaſt vnto the furtheſt Weſt, Shall Tamburlaine extend his puiſant arme.

One day the mail-man found no village there, / Nor were its folk or houses seen again; / People came out from Aylesbury to stare – / Yet they all told the mail-man it was plain / That he was mad for saying he had spied / The great hill's gluttonous eyes, and jaws stretched wide.

[the squirrel] whisks his brush And perks his ears, and stamps and scolds aloud