How to use NTC GPRS for FREE

Trick 1
I have Nokia N72, so basically, number of Nokia sets would behave the same for what I am gonna describe here.
Now, getting to the main thing, I browse the web via Opera Mini (Latest Version), when I am donewith browsing and want to close the session, I would rather searchfor a number “202000000″(nine digits) and when the search result is presented, you can click on the number to call the numberwithout having to close the OperaMini. The IVR shall tell you that “You cannot make call to this number ” and shall end your call by itself. When you call, for some 3-4 times to the same number repeatedly, the gprs connection that had been kept on hold will be closed by the network itself. So you are not billed for the datausage from your cellphone.
Try it urself, and comments are welcome.
Trick 2
Browse data upto your baln. limitthen transfer your baln. to other no
Trick 3
If any of above don’t work for you, go with this:
Browse net starting from evening time 6/7 pm,use GPRS within your baln. limit when you are done leave net idle and sleep,in next morning just try toopen some page or try to use net then connection goes automatically and you won’t be charged! Somtime connection goes after you use 200-700 kb and ya you won’t be charged