Yes, cingular prepaid does offer GPRS.
http://onlinestorez.cingular.com/cell-phon..._requestid=7163
Now, tmobile's sim are the cheapest and easiest to get, but they only offer GPRS access to their free limited tzones. With Cingular, you get full GPRS access.
Phones: Xiaomi Mi Mix 2, Samsung Galaxy A50, ASUS zenfone 3,
Sim cards: AT&T (Contract), 3 UK, Piranha Mobile