The large flat rate is $15.45 (plus .75 confirmation if adding it) or if done online $14.65 (free delivery confirmation)
Med flat rate is $11.35 (plus .75) or $10.85 (free confirmation) done online
If sending regular priority you can save anywhere from $1-3 using the online services which has saved me quite a few times on not actually losing money when I ship.
I forget what company it was, but someone (elsewhere) was talking about what one company charged for shipping so I went and looked at their site. It explained about their shipping and such, but I they said they ship ALL their plants with the soil (including daylilies) so this would explain why the shipping was very high.
I remember there was 3 different starting rates. One set of states were $17 plus more for each one added (can't remember the exact $$$ for added ones), then the next set of states were $19 plus more for each added, and then there were a third set of states that were $21 plus the added extra for more. So depending on where you ship from or to there could be at least 3 different rate prices, not just the one when crossing the river.