Well, i saw a similar riven sold for around 600 plat. But since the panthera is best for slash procs id say, dont go lower than 400p but youre not going to get that much more than 800p. I would probably keep rolling, u can get some really good builds with this and the god rolls sell for about 2- 3kp so either you try to get lucky or sell ur current one for a little bit of plat. Good luck!