At that price Jeannine, yes - great. I pay much more. But I too find the outlay a bit iffy, since I may change my mind & do things another way.
But NOT one time things, Emma. I've twice had to re-sow some of mine this year through carelessness.
Yes, of course, compost is necessary too, for so many things, but it's the 'entity' of the Jiffy that I love. And the visibilty of progress & never a stuck-in-the-tray-plug as I've so often had.