IM3,cheapest GSM Provider with bad Network

Im3, one of the operator of celluler phone provider under management of Indosat.this Provider at begin refers to the Youth user celluler in indonesiawith their priority cheap short messages service ( SMS ). this program be uncontrolled after im3 was launching cheaper price than before that is 0,1 Rupiahs ( 100 sms bonus) if sent 10 short messages service 00.00 - 12.00 dan 12.00 - 00.00 ( 12 pm - 12 am and 12am - 12 pm ).

this program was interested by sms mania.but it make one new problem, that is too difficult to make call to other number,both to same operator or others. now, there is one question,what is better cheap Provider with bad Network or expensive provider butgood network ?