Guys, I'm currently on Talk More 28 Maxis plan. Since my phone is able to fit dual sim, I've bought the new hotlink sim pack with free basic internet. Since I don't want to keep the 2nd sim (that's being used for internet only) because I need to keep it active every month by topping up RM 30, I would like to have internet on my Talk More 28 Maxis plan sim. What's the cheapest one I can find?

I just need to internet for my whatsapp so the 64kbps internet is good enough for me.

Straight to the point:
I want basic cheap internet for my Talk More 28 plan. How cheap? Free if possible

Thanks for the reply. I'm aware of this add-on data plan but I'm not using internet on my phone except for whatsapp. The cheapest data plan might be overkill for my purpose right?