It all depends..
A basic rebuild, in my mind, consists of the following:
New thrust bearing
new thrust bearing seals
New shaft packing seal
New bowl bushings
new bowl seal
new wear ring
new or "reman" impeller (reman impeller: machine the pilot undersize and clean up the leading edges of the blades)
if necessary, sleeve the shaft if it's worn where it rides on the bowl bushings.
Clean up the leading edges of the bowl vanes
Replace all nyliners, nozzle O-ring, and gaskets
The labor here should run you in the $500 range, and the parts anywhere from $300-500 depending on what you need.
If you want it "blueprinted" as some call it, or simply done right as far as I'm concerned, then you will spend more money having the impeller machined on the shaft to eliminate runout and size it properly for the wear ring, have the entire impeller/shaft assembly dynamicaly balanced, measure/adjust all clearances, clean up all rough cast surfaces, most likely do some impeller work (indexing the leading edges, cleaning up the surfaces, "detailing") and reassembly. This can cost anywhere between $1000-$2000 depending on who does the work.
If you need a new impeller or shaft, depending on the grade of parts purchased...things can get expensive quickly.
PM me if you need a referal on a good pump rebuilder.