Usage based data plans

The mobile operators intend to introduce usage based charges for their data plans, instead of unlimited usage. Details are shown in this Business Times report:

StarHub, SingTel may revise charges to deter hefty usage
By JOYCE HOOI (SINGAPORE)
The telcos' crusade against virtually unlimited mobile data usage might soon be upon 3G shores.
StarHub and SingTel are taking a good look at revising their 3G price plans, the two telcos told BT yesterday.
StarHub said that it may 'review current (3G) pricing plansand consider introducing usage-based data pricing', in response to BT's queries.

I do not mind paying usage based charges. I have a plan that limits my data usage to 1G, but the actual usage is only 500 M a month. I have now upgraded to a cheaper plan that provides 16G, but I don't think that it is necessary.