Somewhere between $100-200. Though now it's more like $20 cause soul and enchanting shifting is amazing
Enchanting Shifting is much better than Soulcraft Shifting.
I've turned 5 Pieces of an Elga set and a leftover Elga Wing, all +20, into the 6 pieces of Hero Galaxia I wear now all at +16-19. Then I proceeded to finish them off at a lower and reasonable rate. 1 insurance per shift attempt minimum. All it ended up costing me was the money I lost from Sockets on those Elga pieces. Some pieces I finished right away while others I got to use the +20 event to finish. All it costed me was a handful of insurance and the enchant shifting marbles. Enchant shifting was how majority of the server transfered their godly elga sets into godly Galaxia sets as well as the cheapest means of Zauharant->Elemental Elga.
I just wish Soulcraft shifting could use Normal Insurance as well. Because people never use it due to it requiring it's own insurance which very few even have. Also it's rates are extremely low for artifact/legend shifting.
I've had instances where I +20 from 19 in 1 try. In the end it's all still chance. Just hope lady luck is on your side. Also don't forget we were once at a stage where we had half the insurance for the price we are paying now. 5 for 100 im. Going to 20 has become considerably reasonable compare to before. In all honesty I find +20-ing an item to be cheaper than soul crafting at least. In terms off gold you end up spending a lot on souls. In terms of cash you might want perfect stats on legend and spend a lot on randomizers or resoulcrafting your item. At least getting to +20 is a straight forward goal.
Soulcrafting does seem more expensive. Take any level 70+ weapon. A soul stack just for Advance>Special, slightly over 2 stacks for artifact, and about 3400 souls (Nearly 3 and a half stacks) for Legend. And the initial chances with the gold costs. I've re-legended my Zauharant three times because it was just too good to randomize and I regretted it whenever I rolled Intellect or Max/Min Magic Attack.
Enchanting isn't as bad as anyone can put 600-1000g into an enchanting spree and if lucky have some beautiful results. Where Soulcrafting 600-1000g often gets wiped instantly once you've entered endgame.