Home Depot has 6.5” Mums right now for only $2.98 each. This is the lowest price I’ve seen so far this season and the colors are just gorgeous. I was able to fill the three pots on my front steps for under $9.
If you’re looking to fill in a few flower beds, Home Depot also had big pots of perennial day lilies for only $5. They had already flowered but if you plant them now, you’ll have gorgeous blooms next year.