Get some CD turntables.
Get some DJ software.
Consider a digital turntable controller.
Just line your computer into some speakers.
Get a digital interface.
Get an external hard drive.
Get two direct-drive turntables
Get an appropriate pre-amp for your turntable, if necessary.
Get the necessary vinyl hardware.
Get a mixer.
Consider getting your own PA speakers.
Consider investing in a DJ starter pack
Start collecting a sizable amount of vinyl records.