Many of the nurseries rotate what is for sale each year, some have a three year rotation, some have more years. It depends on how many of them sell and how rapidly they grow.
Hollingsworth Peonies
Solaris Farms
Adelman Peony Gardens
Klehm's Songsparrow
A&D Peonies
Looking around at one of those growers will give you a root that will likely bloom the first year too.