After turning on the mobile phone, the SIM card connects to the nearest GSM tower from the mobile provider and you can make and receive phone calls. As explained below, you can either use it on your regular US smartphone (if your phone allows), use it in an old phone that is compatible with your SIM card, or buy a cheap phone (either at home It must always be available, but it is also a double-edged sword for travelers looking for a little rest and relaxation, as everyone who calls your regular number comes to you. A low price means your phone has been subsidized and you are probably in a 1-3 year contract where the carriers try to repay their money (and more) during the term of the contract. Additional packages are also available (listed in the link) .Over 2,29 EUR. Estonia, TeliaSonera Group, Super Prepaid SIM Card. for 1 EUR. on this page. jpeg' alt='Where to buy sim card for unlocked phone' title='Where to buy sim card for unlocked phone'>Buy a mobile phone SIM Buy a tablet SIM Step 3: Use as soon as your ads are related to: purchase Unlock SIM card in connection with purchase Locked SIM card Prepaid SIM card for unlocked phone