BHB is in michigan, not sure if they have any yellowbellies on their site
http://bhb-reptiles.myshopify.com/
I also think Evan stahl is in michigan but I'm not 100% sure on that. hopefully others will chime in with some other michigan breeders.
http://www.evanstahl.com/Evan_Stahl_Reptiles/Home.html
I would call myself a breeder since I got my first clutch this year but unfortunately I don't have yellowbelly in my collection yet.
Depending on size I'd say yellowbely 'hatchling' females could go between $175-250 at the most? since I've seen hatchling males at $100-150 .