Can I go through TSA PreCheck with my Global Entry card

No, to receive TSA PreCheck you have to include your KTN while making your airline reservations so that the TSA PreCheck indicator is present in your boarding pass. You cannot show your Global Entry card to go through the TSA PreCheck at the airport.

Do I need both Global Entry and TSA PreCheck

No, you don't need to have both Global Entry and TSA PreCheck. If you have a Global Entry membership, then all the benefits of TSA PreCheck will be automatically included in it. While booking flight reservations, you must enter your Global Entry membership number or PASS ID in the field for KTN to take advantage of the TSA PreCheck benefits at the airport. You can find your Global Entry membership number toward the bottom of your Trusted Traveler Programs account.

How can I get Global Entry for free

Many credit cards reimburse the application fee of both Global Entry and TSA PreCheck. Some of the eligible credit cards include select American Express cards, Arvest Visa Signature, Capital One Spark Miles and more.