Prepaid mobile recharge with bonus

Recently I tried to recharge my Airtel prepaid mobile using ICICI Bank online prepaid recharge facility. Its a bonus to do this recharge. I recharged for Rs 500 and got a talk time of Rs 650 (ofcourse mine is lifetime validity and hence should get full talktime on every recharge), but getting Rs 150 extra talk time is bonus.

So, I thought it was for some seasonal offer, but it is happening since last few months and not just me all my friends are trying this and are getting Rs 150 extra talk time.

If any of you want to recharge their prepaid, then try it via ICICI Bank and enjoy the extra talk time. Also, try recharging for other currency and let me what kind of variations happen, also let me know if it happens for other services like Hutch, Reliance and others. You can comment here or drop me an email.