I refuse to deal with these things anymore, although I had used a Tracphone for looking for work in 2007.
In late October, I went around looking for a low-usage cellphone (since voice mail on the home phone was incomprehensible to add, and pagers stopped being cheap some time ago). I ended up at Meijer, struggling to calculate the cost-per-day. It didn't help that there were loads of tiny type, which is just designed to stop you from comparison shopping. It also didn't help that the phones were hanging on locked hangers, which stopped you from turning them around to READ THE TERMS. After finally making my selection (having to call a service person over with each phone that I wanted to look at to get it unlocked), I confirmed that I had the lowest cost one (Virgin Mobile), and then left.
The next morning, I opened the package and read the instructions ... and then noted it said "30-day plans" on the list of plans. The minutes refill card claimed that the phone only needed to be refilled every 90 days. Then in smaller type, it said the minutes were only good for 30 days. I GOT SCREWED ... and I had tried like hell to NOT get screwed.
Well, as you might suspect given the tone of this story, Meijer didn't honor a return on these things, even though the phone was only opened and charged, and the minutes card was not scratched off. The Meijer receipt never said that these things were NOT RETURNABLE.
My advice now: Consider all your options. Read EVERY word, no matter how small (and the type on those cards is VERY small).
As for me, I've gotta dump this stupid phone and minutes card on Craigslist, probably at 50% of the price, and chalk the lost money up to a LESSON LEARNED. And that lesson is: The phone industry is crooked.
(And I'm never going back to Meijer.)
As for my continuing needs, I have a friend who has an existing Verizon plan, with shared minutes for he and his wife. He said that the plan allowed adding a line (another phone and phone number) for $9.99+tax per month, which will turn out to be about $13. And Verizon offers free phones for such things, which means you buy the phone and then apply for a full rebate, so you only end up paying the tax. Of course, there are better phones with lesser rebates, with price differentials of $20 on up, if you have more expensive taste in phones.
So we researched this, and then went to a Verizon outlet, and with their kind assistance, we selected a similar phone (they didn't have our first choice in the store), and they waived the activation fee ($25 or $35, depending on who you ask -- the cust svc line claimed that during November, such a fee would be automatically waived if done on Fri-Sun), and now I have a cellphone for CHEAP.
Of course, my friends and I trust each other, so that's what enabled that. I didn't want the cell for gabbing, so their shared minutes with me are not in danger. And the cell's airtime is free after 9pm and on weekends. I also don't do texting.
Good luck in your search for an appropriate communication device. After my experience, hopefully you won't make a similar, critical math mistake with your costs, which is all too easy to do considering how DECEITFULLY that these things are marketed.