You basically have two options
-The Tarot, which requires an extra mounting bracket to fit the Phantom, runs around $200 total.
but it's solid and works great.
-or for less, you could get a goodluckbuy gimbal for close to $100, but comes with no documentation of any kind, and has it's quirks.
the Tarot is arguably more plug-n-play tho, especially if you buy one pre-assembled (some vendors sell them like that)
But all gimbals require a bit of learning