Sigma prepaid LLC is a prepaid telecom company. Sigma sells private label phone cards as well as other companies' cards to ov ... er 1000 of its retail locations and thru small and large distributors, caters to over 10,000 retail locations in NY. Sigma has over 100 private label phone cards from 10+ Carriers. Sigma maintains an exclusive relationship with five of the top seven carriers in the nation. Sigma is on its way to establishing itself as the most aggressive and leading distributor in NY. read more