Verizon, AT&T, or T-Mobile? Which carrier do you choose? There are a three main items I would look at when choosing which carrier.
Price - If you are going to be purchasing a few lines, or using the lines for a long period of time, the price of the plan is going to be an important factor.
Coverage area - More than likely you won’t have an issue with this, but there are still some areas that either aren’t covered or have poor reliability with certain carriers.
Reuse-ability of the SIM card - AT&T SIM cards can be removed from the product they are in and put into a new product. Verizon if you switch devices, you must deactivate the SIM card and then reactivate it for the new product. This causes you to loose any of the data you have remaining for the month. T-mobile cards can’t be reused. Once they are used they must be thrown away and a new card purchased for the new device.