Noted you interested in the CB Shell CC. Click below link where gerrardling have shown the net cash back and you get less in returns when you spend more with it

http://forum.lowyat.net/topic/1798403

Also noted you spend up to RM 2K (when your income only about RM3K per month ???), so you may or may not need to have more than one credit card to maximize cash rebate.

First card to get is the OCBC Titanium MasterCard which earns you 5% for Petrol, Dining and Telco Bills. Annual income requirement RM36K/year. The reason why I mentioned you need to get more than one card is because this cash back for the OCBC TMC is capped at RM50/month. So if you do spend RM1K on expenses that earn you 5% cash back, you would have hit this said cap.

So, assuming you hit the monthly cap of RM50 cash back, next card to get is the Maybankard 2 Cards where you earn 5X TP every day PLUS 5% csah back on Saturdays and Sundays. And the MBB 2 AMEX should be accepted at your Shell station.

With the combination of the two cards mentioned above and RM2K spending, you can earn up to RM100 cash back per month ( and that's not including the Treats Points you can earn with the MBB2 AMEX) with proper planning   

So go apply for the above mentioned cards concurrently.

However,  don't be disappointed if your application is rejected if you don't have any credit history. People with many credit cards for years also got their application rejected by OCBC. In the event OCBC rejects your application, get other credit card first and after 6 months to a year, when you have a good credit history, then you would have no problem getting the OCBC TMC.

And since you are new to credit card - suggest you read my articles for beginners by clicking here to the prelude.