If Scott bought 20 daylilies and 10 pots of ivy it would cost twice as much: $320.
Micaela bought 1 daylily and 10 pots of ivy for $92.
If we subtract what Micaela bought from what Scott would have bought for twice the money we can see that 19 daylilies must cost 320-92=$228.
So one daylily costs 228/19=$12, and that means 10 pots of ivy cost 92-12=$80, making 1 pot worth $8.
(10 daylilies plus 5 pots of ivy cost 120+40=$160, which confirms how much Scott paid for his plants.)
So a daylily costs $12 and a pot of ivy costs $8.