Please consider the following:
TSA Precheck is good for domestic air travelers. (Government Fee $85). You can use the fast lane at security on departure.
If you travel abroad/outside of the USA, Global Entry is better for you. (Government Fee $100) You can get TSA Precheck free and use the fast lane on re-entry into the USA.
Click Here For Global Entry Application
If you are already a member of Global Entry, SENTRI or NEXUS, you do not need to apply for TSA Precheck.