When can you buy irises?

Excuse me, I'm interested in purchasing some irises but I'm not sure when the best time to buy them is. Could you please provide some guidance on this matter? Are there specific seasons or times of year when irises are more readily available and perhaps more affordable? Also, are there any particular varieties of irises that are more popular or in demand at this time? I'd appreciate any insights you can offer on the best time to make a purchase.