When a deal sounds too good to be true, it usually is. Collector packs may be different, however, due to the nature of the special presentation folder. Telecards should contain complete instructions on their use. Check on these prior to purchase. However, many offer a way to purchase additional time, usually by charging the additional time to your credit card.
Many companies offer lower rates upon renewal.
It is less expensive for the Company to re-charge a card rather than manufacture and sell a new card. You won't be cut off during an important call. Instead, your call will be held and you will be offered the opportunity to add time. Eliminates the concern of having a little time left, but not enough for the call you want to make. The time remaining won't be wasted, it will be added to.