Here is 100% working trick to unlimited use BSNL 3G at normal cost of NORMAL GPRS
First of all Buy a normal 2G bsnl’s sim and keep balance 50+ rs. now active gprs by sending GPRS PRE to 53733 It will be activited in 24 hours, after activation get gprs settings by calling customer care
Now do e-reaharge with 230 rs (or whatever unlimited plan exists in your area)
in it, After activation You have to change only one thing in your 3G enabled cell.
Go to settings>tools>settings>phone>network>network mode>now select UMTS
THEn do manual searching for network u will find bsnl 3G network there wid small 3G logo along wid its name,select it as default
Now see your data signals logo, it is converted into 3G You will get near about 500kbps to 1200kbps speed
Remember use BSNLEGPRS or BSNLPREPAID as your access point