A wideband setup will cost you one heck of a lot less than a tune up shop, and if you want you can plug the bung, and put the system away in a cabinet for the next round, so it's not money down the tube
Some time ago (and there certainly are others) I bought a combo innovate setup with dash gage for under 140. The bungs are same thread as an 18mm (Ford) spark plug, so you can easily plug them if you want to pull the sensor out.
Most the wideband setups have a logging feature that you can retrieve with a USB or serial cable, so you can make a run and log the results.
