SD Rebel
Spends too much time on here
Looking at the Flow FX muffler itself, its only $43. I wonder what a muffler shop would charge to install.
Flowmaster 71229 Flowmaster FlowFX Mufflers | Summit Racing
Depends on the shop, but for example my Flowmaster Outlaw was $110 for the muffler, I paid total out the door with tax $278 for everything. Which includes custom hangers, welding, etc.
So about $168 in my case for labor, piping, materials and taxes. I've seen it done for cheaper, but the shop I used was known for their great welding and probably higher labor costs.