The iPad, iPad Mini and the iPod Touch are three devices that do not come with the Phone.app. That's obvious. But that doesn't prevent many people from making calls using their iPads or iPod Touchs.
While you cannot make real cellular calls with the iPad (unless you're one of those geeks that hacks into the firmware and hardware), there are definitely many ways to call via your iPad (and iPad Mini) through 3G/LTE or Wi-fi. That's right. We're talking about VoIP.
You need apps to get things rolling. To make VoIP calls, you'll need the best apps that work on the iPad and iPad Mini to connect you to your friends.
Needless to say, Skype remains the most-used VoIP app for almost all devices including desktops. On the iPad and iPad Mini, it's even more so. All internet jokes on Skype notwithstanding, it has grown to be the the most popular cross-platform way to make voice/video calls. Skype for iPad and iPad mini can make VoIP calls to any number across the globe. And you can also use it to make free calls to other Skype users.
The best thing about it is Skype's charges are one of the most nominal ones.
Facetime in iOS 7 (audio only)
If you're making a call to someone who is on a Mac, iPhone or other iDevices that support Facetime, you could use Apple's default feature to make calls. Facetime – unfortunately – is for video calls only at least till iOS 6. With iOS 7, you have the option of making audio-only Facetime calls which almost makes Facetime the most-preferred app to make calls over Wi-fi or 3G.
WePhone is an VoIP alternative that has received some good reviews over the years. One of the greatest benefits of WePhone, over Skype, is the absence of having to go through creating new user accounts and then managing payments through it. You can buy WePhone call credits as an in-app purchase. The app also lets you record calls.
Line2 was one of the top 10 apps on NYT and has since bagged some top-notch awards for its amazing VoIP features. Line2 works on a $9.99 monthly subscription that can be set for an auto-renewal through your iTunes account. When we're talking about Line2, we're basically talking about a totally hassle-free, almost-iPhone-like calling experience for the iPad, iPad Mini etc. Line2 also features unlimited texts to US & Canadian numbers, conference calls with up to 20 people (something WePhone/Facetime lack), call waiting, transfer and forwarding.