tuning process involves checking the specs on the bow :

axle to axle length , tiller, brace height

then checking if you cams are in tune and wear on the cams

then see if you have cam or idler lean oil shafts for axles

see if center shot is right

paper tune bow to see if arrow is flying true

see if cable and string are not worn if so replacing and doing all of above

making sure limbs are not cracked or twisted

this should cost anywhere from 50- 75 dollars ave.