>>279726841
You would need to buy 3 base stations, 3 trackers, and optionally, although very highly recommended, track straps.

All in all this will cost you around the ballpark of anywhere from $500-$700. If you decided to upgrade to the Index some day, you would already have the base stations. So you'd be paying $750 for the Index + controllers instead of the $1,000 for Index + controllers + base stations.

Hybrid setup is kinda shit to be honest, it works but the tracking won't be as good as if you were on a steamVR headset.