A new barrel plus instalation and blueing runs around $500. +. You can find take off barrels for around a $100. and then whatever a gunsmith will charge to install it as you'll want the lettering to come up right and be sure the headspace is correct.
I have reciently bought a takeoff Savage Varmint 22-250 with custom target crown and low round count for $90. A Rem LVSF 22-250 Fluted SS for $100. and a new Rem. Varmint Special in 22-250 for $85. these are all shipped prices.
Talk to the gunsmith you plan to use to install the barrel, he might have access to someone that builds customs on Model 70 actions and has some takeoffs laying around.