You can't just base it on talisman prices, gotta think about supply and demand.
There is plenty of people (especially turks) which would offer crazy gold since there is probably no other ones for sale, and talismans are hard to come by. Also alot of people prefer to buy pimped weapons.
The fact of it being a staff many people would want it, and bring up the price. Look at normal nova weapon prices...staffs are 2-5 times more expensive than most weapons.
If you made it +8 and used a B elixir on it, the base value would be like 7-8b for talismans + 1-2b for the B elixir, 2b for it being +8 = 12b + another 2-5b based on demand
