The 16-GB, Wi-Fi-only iPad Mini sells for $329. The same unit at AT&T, Sprint or Verizon costs $459. For any model, add $100 to Apple's list price for each 16-GB increment. The iPad Mini has been selling since November 2012. Google's price for a Wi-Fi-only Nexus 7 is $229 with 16GB and $269 with 32GB; both began shipping this week. Coming later this year are cellular models for AT&T, T-Mobile and Verizon at $349 with 32 GB only.