I have a hard time understanding why wholesale would ever be more expensive than retail......unless it was the quantity involved.

Vermiculite is vermiculite - you just want a medium grade, not too fine and not too coarse. Personally, I prefer perlite over vermiculite for any potting mixes as it won't break down and collapse like vermiculite will. But for a seed starting mix where the plants will not be growing on long term, you could use them interchangeably.

sorry, I meant buying retail...
I did just purchase a large bag from Menards and will use it for a mix to start seeding..also for hypertufa..they also have the bigger bags of perlite ...great for mixes....
Thanks gardengal...