CHENNAI: IDEA Cellular, a leading GSM mobile services operator, has come out with a new special tariff voucher offering all STD and local call rates at just 48 paise a minute. New prepaid subscribers of IDEA in Chennai and Tamil Nadu can purchase any of the two new tariff vouchers priced at Rs. 37 and Rs. 95 offering a talk time of Rs. 15 and Rs. 70, respectively.