@larand My regular line is on AT&T, the rest of my family is using Cricket. That said, by the time you add four lines to an account, the fifth one is free, assuming you stick with the $40/mo plan. I've been using that to acquire (and test) cheap Android phones for work.
Cricket is basically AT&T throttled to 8mb/s on LTE. Family seems to be reasonably happy with it, except my daughter who frequently goes over the 4GB monthly allotment and gets slowed to 128k/s :P
// @matigo