While they can be cheap, one must be very careful.
When an unrecognized charge showed up on a credit card, I could click to get a phone number, but the phone merely states unless you pay for service you do not get any technical support, or opportunty to speak to a live person, or even billing assistance (not stated, but clear) since other numbers give the same menus, and same recordings. I am certain they count on you paying say $1.99 every month rather than pay a fee of about $6.00 per month to have your billing questions answered (or even once to get rid of the fee),
If you end up with several devices you need careful records so you can logon correctly (one E-mail for each account), and probably use different credit cards for each phone. I bought several phones for the family with one credit card, and their billing does not tell you which phone or device created the charge, or what it is for.