When I ran my shop I would do a re-ring on B18-B20 for about $1700.00 plus taxes. That included new standard rings, rod bearings, main bearings, new oil pump spring, new timing gears, cam and lifters, valve grind, shim the springs, check the rocker shaft, new gaskets, all fluids and an oil filter. Water pump and clutch would be extra if needed. That also included all labour- about 20 hours. Car delivered to the shop, delivered to the customer running and ready to go. Warranty was one year, unlimited mileage. Never had a comeback. I used to service these "re-ring" engines, and lots went past 50k miles until I shut down the shop and stopped tracking them.
New pistons are nice - but expensive. I did install Mahle and KS pistons for about half of the engines I rebuilt (50 plus over the years)and at the end Mahle pistons were over $500.00 for the set of four in Canada. Figure $25.00 a hole to bore and hone. Sometimes new small-end bushings in the rods. Sometimes re-size the rod big-ends. Cam bearings if needed - that's about $150.00 for the three. It adds up, so that the price is closer to $2500.00 or even $3000.00.
But when the pistons were good, much of the time, and set of Hastings rings was $40.00, I honed the blocks myself in two stages, and all was well.
It's a judgment call - when to do what. There is repair, rebuild, restore, overhaul, all descriptions of the extent of the work, and it all costs.
I hope this helps.
Rhys