Start with the IAC, you can clean it for free, replace it for $50.
If you want to troubleshoot things like this yourself, you'll want a scangauge to give you a digital readout of things, rather than rely on the cluster gauges.
Normal idle at a cold start would be a surge in the 2K RPM range, then a gradual drop ~1500... ~1000... ~900... finally settling in the ~750-~625 RPM range depending on accessory load (AC). In drive it should stay ~650 and not shut off. Some tracs have had the idle speed set too low and would idle in the 500 RPM range, causing annoyances more than anything.
There is an idle set screw which may need adjustment, although it has a nylon patch to prevent it from unscrewing with vibration. It is right under the accellerator cable to butterfly valve connection at the throttle body. You can check the idle speed project in here under projects for more info.
The MAF costs upwards of $100. You could attempt a cleaning of it, but it has high tension wires which can snap easily. There are 2 opinions on cleaning, you can search for the debates here as well. Use caution.
Check under the hood to make sure everything that needs to be connected is.
