In my article on the (possible) vanishing monthly discount for AT&T Family Share Plan users, I included a table with some cost estimates for a given phone and service.
Given the popularity of that article, I've done a bit of work to clean up my spreadsheet to make it usable by anyone. You choose which phone, and the size of your shared data plan, and the calculator spits out the results (click the image at right for a large version). As you can see, I've added a column for the Next 18 plan, too.
Download the calculators here. The zip archive includes versions for Excel and Numbers. Usage is pretty simple: Click the two red-text cells to set the desired iPhone and your data plan size, and that's that.
To summarize what I saw in building the worksheet:
- If you're on a shared plan with under 10GB of data, going contract will save you a bit of money over two years. You'll give up flexibility over buying or Next, though.
- If you're on a 10GB or more shared data plan, then going Next or buying outright is definitely the way to go. More flexibility, and you save money—assuming you do not upgrade at 12 or 18 months under Next by just sending in the old phone!
Note: I do not vouch for the accuracy of this thing, beyond its role as a "what if" tool. I took the values from AT&T and Apple sites, but those figures could change. Feel free to modify as you wish; it's a quick and dirty spreadsheet with minimal formatting.