I use several of the Stiller actions. Some are Remington clones and start at $900. It includes the action/bolt/fire control and recoil lug, but no bottom metal, mag box, follower, spring or guard screws. A PTG Bottom metal, mag box, follower, spring and guard screws will run you about another $200.
If you were to purchase a Remington SPS for about $400 have it fully blueprinted (correctly) for about $150 plus a Holland recoil lug $40 you'd be at about $590 and you'll have the factory trigger to start with and the factory bottom metal, mag box, follower and spring.
Custom Action with bottom metal $1100
Remington Blueprinted $590
Difference $510
You can keep upgrading the Remington with more performance parts as well.
PTG Bolt, Fir Control, Handle attached and extractor you'd have about an additional $300.
Now your at $200 less than the price of a custom Stiller action. You can build off of a Remington a little cheaper but all depends are how far you want to take the Remington upgrades.