If money is tight, ultimate horsepower is not a goal, the block is not too worn and it already has certain types of forged pistons, they can run with as much as 0.005" of clearance, since they expand greatly with heat. In such cases, you can get away with a good honing and re-use well cleaned used pistons with new rings.This is a "freshening", not a complete overhaul and is commonly done in all kinds of racing engines. Honing is far cheaper since less set-up is needed and you wind up with stronger (thicker) cylinder walls.
But if you have cast (stock or hypereutectic) pistons in a used block, an economy freshening will not work and you're stuck with overboring and new pistons. Good luck.