Do you need turntables? The requires a mixer, 2 turntables and software/audio interfaces.
Since you started as a digital DJ, try getting something like a VCI-300 with traktor or "sigh" serato itch.
djtechtools.com
skratchworx.com/newspage.php4
However if you like to go the turntable route. Bring out the wallet.
2 Technics 1200s (buy it used, if you dont keep it, still resable.
High quality mixer (this can go from 2 channel to 4, 6, or 8. Audio interfaces in it. Midi)
2 Neddles (depending on your preferences)
Software. Traktor Scratch Duo, Traktor Scratch Pro, Rane Serator Scratch Live.
From those you will get to pick your audio interface.
Figure out what you want to do.
Whatever you do, DO NOT PICK SERATO ON THE BASE THAT OTHER PEOPLE USE IT. This also applies to Traktor too.
BTW, also do you want to mix videos?