If you want to purchase VRIdge go to RiftCat desktop app, after pairing your phone, at the "Play" screen. You will see button named "Unlock VRidge" which will get you to the order page or you can go directly to this page.
You can also buy VRidge code on G2A, link here.
Any RiftCat's product code can be redeemed on this page.
GameWarp is an addon to VRidge which allows you to play non-VR games like Witcher 3 or GTA V in VR. You need to have purchased VRidge in order to purchase GameWarp. If you don't own neither then you can buy both at discounted price. Visit THIS LINK to learn more.
Please try the free version before purchasing!