I use 8 inch for the smaller plants with 1-4 eyes. And the 10-12 inch for the larger hostas. My U. Albomarginata (which is HUGE and a monster in the 3rd season I've had it) is currently in a 18 inch pot. But I think for a couple of seasons or longer the 10-12 inch pots work very well. I buy mine at Walmart mostly. I use the weather resistant (glossed inside as well as out) and they work very well for me.
Here is a picture of all my "baby" hostas in their 8 inch pots.

There's a disadvantage to the idea you propose. Any small plant in a large container is in danger of not ever drying out. Hosta like air to their roots.

bk

BK, if you would have read carefully I was implying the size of the container needs to fit the size of the hosta and not be too much. My U. Albomarginata is a monster and has had to be moved up in container sizes but not all need to be. That the 10-12 inch pots are just fine for the larger hostas but the 8-9inch, for larger, they won't fit... And they don't.

Brandy, I believe BK's comment was directed at Old Dirt.

Old Dirt, no hosta will ever stop growing and no planting medium will ever be permanent. For both these reasons, as well as BK's too wet warning, its best to size the pot according to the hosta size and repot as needed.

tj

To get started with hosta in pots, I'd suggest beginning with minis and smalls.

Be sure to use a very well draining potting medium like pine bark fines mixed with perlite.

Terracotta or stoneware pots dry out faster and need watered more frequently than plastic.
:-)
Deb