Barrington 

I am planning to get an ipad for the occasional trades (options & stock) and monitoring my positions/account while at work/commuting. Does anyone know how much data it will need? The phone company reps. don’t have a clue and just want me to subscribe to the most expensive unlimited plan.

Position plots actually don't use very much data. I have an ATT hot spot for access on the go when there is no WIFI
and for times when power or internet may fail in my office. If used sparingly only for travel or emergencies I
believe 1 G of data covers my needs. But your needs may vary.

I always worry about trading on mobile connection, if it goes out you get stuck up the river without a paddle. otherwise I do like to monitor my positions on the tablet.