Spine bow base for ice shot

I'm trying to follow a guide to crafting a bow for my ice shot build, the first thing I need is a spine bow with a fractured >=t4 + physical damage % modifier but I'm having trouble finding one and have no idea how much I'd expect to pay for one; I only have a few divines to my name and the only hit I've had in trade chat wanted 90d for a t1 base (waaaay out of my price range), if I wanted to find a high t4/low-mid t3 roll could I get the price down enough to be able to afford it or are bases like that rare enough that they'll always be in the double figures?

I'm still a relatively new player, this is my first and only build, and this would be the first crafted item I've made, so I have no experience at all to be able to base price expectations on, hoping someone will be able to help clear this up for me.

Cheers