Which online brokerage to use for US stocks for someone in NS?

I am looking at IB , TD and SCB. I am planning to do a lump sum every 4 mths or so. I know IB is the best in terms of fees but my worry is that once I complete NS I won't have a regular income to invest as I will be going to uni. Should I use IB regardless or TD since they just remove their fees for US stocks or SCB which has slightly lower fees than TD if I am not wrong. Thanks !