In postpaid-telecom HIGHEST commission is given by TataDocomo and BSNL (avoid BSNL-postpaid though) at 0.7% (70p for 100Rs bills) and lowest being AirHELL at 0.2% (20p for Rs100 bills)...
In prepaid LOWEST commission is given by Vodafone 2.0% (Rs2 per Rs100 TopUp) and highest by MTNL-Mumbai at 4% , MTS at 3.5% , TataCDMA at 3.25%... TataGSM and BSNL 2.25 to 2.75%, Axis of Evil (A + V + I) has different packs/recharge/commission on each circle (only national-pack merchants like me can recharge other circle AVI users)... Obviously AVI gives lowest commission and they are planning to reduce it again in a month or two and others may follow soon...
In recharge shops, the shopkeeper gets 0.5% to 1.5% more commission than oxigen merchants (obviously the difference amount was given to oxigen and oxigen-distributor/dealer here).. For Eg:- My relative is TataDocomo postpaid dealer and he gets 1.5% commission (highest in postpaid afaik) and we get 0.7% and for prepaid he gets 3.5% and we get 2.25 to 2.5%
Further we can do DTH recharges for all providers... SunDirect 3.5%, Videocon 3.0%, TataSky and BIG TV 2.5%, DishTV 2 to 2.5%... And few more are there like easygo insurance, flight booking, hotel booking, etc.. But I have used none other than telecom recharges and bill-pay (postpaid)...
I got this account mainly to do online recharges for my roaming circle numbers (2G/3G/EVDO data) and to pay all my postpaid bills FULL-AND-FULL for my personal use only... So commission is not a big issue for me... In the last two months I have saved Rs300 (by commission) in 60 transactions mostly TataBillPay and BSNL FULL-TT...
It is much-much better than doing online-recharges.. Atleast your money is safe, if something goes wrong... But for wrong-recharges (recharges mistakely done to different numbers) only Tata and RCom allows reversal (they also may remove this anytime)... So confirm the number more than twice if you are going to be using commercially...
Further there are other mode of operation for oxigen recharges like SMS, mobile MIDP app, GPRS-terminal which costs Rs1000 to Rs2500 extra (one time) apart from the Rs1800 initial deposit...
Please ask if you want any more details... Thanks...