In some ways, though, the pricing is the hook. You can add lines for $15 each. That's not trivial, but easier to justify than a full line. Be aware of the catches, though. This won't help if you want service on another carrier (for backup or better rates, as an example). And if you decide to switch carriers, you'll have a headache on your hands trying to move those lines over -- yes, it's a classic case of lock-in. However, this might be helpful if you want a separate work line with relatively little fuss.