Where to Get Sweet Potato Slips

Had a lot of stuff come up this year, so I think I’m too late to start my own sweet potato slips. I live in zone 5b. I ordered slips in the mail last year from Annies Heirloom, but I wasn’t too impressed with them and a lot of them died. I was thinking of buying some off facebook, but I’d have to drive minimum 70 mi to pick any up. Nurseries don’t carry them near me. Anyone have suggestions?

Sandhill preservation center in Nebraska is a neat place!

I buy a sweet potato from the store, and toss it into a pot. It sends out lots of shoots that I break off and plant into the garden. Sweet potatoes love hot weather, and don't really grow for me before June.