A pair of pistons cost about 200$ for a complete set with wrist pin bearings,unless you just want to do the one bad cylinder.
Boring is anywhere from 60-100$ a hole depending where you go
I'd be worried about the condition of your crank.
If it's just the top end, gaskets cost between 40-70$ if you choose oem. Oem head gaskets are pricey!
If the crank is shot, you're looking between 250$-500$+ for a new or remanufactured one.
For reference, you can find 61x motors for under 500$ for a bare short block.. But of course the crank is in unknown condition unless you tear it down.