In one sentence, describe what the following article is about:

When you’re not in your home country, your service provider will charge you for call minutes, text messages, and even data usage. Before you make call using the internet, make sure you’re connected to a WiFi source and not using cellular data.  To make sure you aren’t using data, you can turn it off in your phone’s settings. On an iPhone, for instance, go to Settings, then choose Cellular. Switch the toggle button next to “Cellular Data” off. A lot of places offer free WiFi now. Try a hotel, restaurant, library, or coffee shop. Voice over Internet Protocol (VoIP) apps converts your voice and/or video into data signals, which are then transferred over the internet. Choose one of the many VoIP providers, then install the software on your laptop, or download an app on a tablet or smartphone.  VoIP is often cheaper than traditional international phone calls. If you’re calling a landline or calling someone without the VoIP service, there will likely be a charge. Some of the most common VoIP apps include Skype, Google Voice, and WhatsApp. While most laptops come equipped with a built-in microphone, some do not. You can buy a portable headset that has headphones and a microphone, and can be plugged into your computer via the USB port.  Look for headsets or microphones at an electronics store or an online retailer. If you want to make a video call, you’ll also need to hook up a webcam. Type in all of the digits of the phone number, including the area or city code. Check the instructions for your app or service to see if you need to add the country code or "+" at the beginning of the number, as well. Some will automatically insert that code if you select the country you’re calling. Many apps can access your phone’s address book if you’re calling someone from your contact list.
Connect to WiFi to avoid hefty data fees if you’re in a different country. Download a free “Voice over Internet Protocol” app or software. Connect a headset if you’re using a device without a microphone. Enter the phone number you’re trying to call and hit the dial button.