Translation of "engangs-" into English

Det er problemet med disse engangs-dansehitene.

That's the problem with chasing these one-off dance records, you know.

Ikke glem taperfars-tilbudet på engangs kameraer og balltrær.

And don't forget our " Deadbeat Dad " discount... on all disposable cameras and whiffle ball bats.

Forresten, det at jeg sovnet var bare et engangs tilfelle.

By the way, when I fell asleep that was a one-time occurrence.