That's the deal ALK is offering this holiday weekend, and you can grab it starting right now.
CoPilot Live offers complete turn-by-turn navigation for the U.S. and Canada. Its features include text-to-speech (meaning it announces street names), address book integration, tap-to-call POI listings, and easy switching between different modes of travel (car, bicycle, walking, and so on).
You'll definitely want to read Dong Ngo's CoPilot Live road test that covers the highlights and letdowns--but keep in mind the app's been updated since then. For example, Ngo dings it for lacking text-to-speech, but it now has that feature.
Still missing, alas, is real-time traffic information, which apparently remains on the coming-soon list. Thankfully, future updates to the app will be free, though any premium services like traffic will cost you.
Even without that option, it's hard to pass up a full-featured navigation app for just $20, especially with competitors like Navigon, iGo My Way, and TomTom still selling in the $70-100 range.