CLARKONOMICS: Here's yet more good news for renters. The number of apartment vacancies at the end of last year hit a 30-year high. That means great opportunity for tenants if you choose to accept the shopping challenge!

What's called "effective rent" -- meaning what you pay -- has been declining around the United States for a while as we've been in a deflationary rent cycle.

Very often, when your lease expires, you may get a renewal bonus like a gift card to entice you to sign on again. But Clark says to take a cue from Jerry Maguire and say, "Show me the money!" You can get real savings by being willing to walk.

Start your apartment search about eight weeks out before your lease is up, unless you're required to give more notice. Landlords looking for prospective tenants are wheeling and dealing right now. You may get a free month of rent, a waiver of the security deposit or a kick-out clause in the event that you're laid-off.

But you only get that power if you're willing to walk out of your current situation when your lease comes up for renewal. If you'd rather stay put, you should still search for apartments and then show your current landlord what you find. Ask if he or she will compete against the other cheaper rents out there.

One special tip here. There's a sweet spot in the market right now with what's called the "shadow market" -- essentially condos that are being rented out by involuntary landlords who can't afford to sell them.

The dangers of the shadow market include a possible risk of landlord foreclosure and the chance that you won't get prompt response on maintenance issues.