Depends on the shop, stay away from the chain-shops (Meinke, Midas, etc.) and go with a locally-owned independent.
I've had individual pieces fabricated in the price range of $3-$70 depending on the part in question (the $70 part required a few bends and HOURS of TIG-welding) and whole systems done as cheap as $140 at an independent, I've never seen a chain store willing to do individual part fabrication, and their systems usually start at about $350-400 and go up.
__________________ 1976 Ford Mustang II Ghia: 302 with a 600cfm Edelbrock carb, Edelbrock Performer 289 intake, Dynomax Blackjack headers, 2.5" exhaust with Flowmaster Super 44s. RJS 11-gallon fuel cell, C4 tranny, chrome 16" pony wheels, fuzzy dice, brown vinyl half-top, and painted in the tackiest color ever (harvest gold, that's why I call it "The Goldenrod").
Also have a 2003 Dodge Ram (lightly modded daily driver/tow rig/office/dining room/home away from home/workshop... I call it "The Big Blue Dawg".) | 
Mustang II exhaust need help finding parts 
