If you're planning a major purchase via the Internet, you might want to do it quickly. Congress is expected to introduce a bill this week that would require Amazon.com, L.L. Bean, Cabela's and other online merchants to collect sales tax on all online purchases and return that money to the state in which the purchaser resides.

I was recently shopping for a TV for a relative, and found that I could save $70 by buying it online and having it shipped to her address. That savings was primarily in sales tax. And while my state requires taxpayers to claim all online purchases and pay the sales tax on them, it doesn't seem to be able to enforce the tax. This is good for bargain hunters, but terrible for local merchants.

For those used to buying $.99 iTunes or other more tangible items, this will be an immediate price hike. Californians, for example, will pay an extra 7.25%. We'll see when the bill is introduced it if also included local sales taxes, which can bump this up to 8% or more for many of us.

Although the bill is strongly opposed by online merchants, the states have suffered a reported 6.1% decline in sales tax revenue due to the recession. Because of this, states are in dire straits. I wouldn't be surprised to see this measure fly through Congress, so don't delay that major purchase too long. You might even consider doing your Christmas shopping now. Where else can you put your money that will bring an 8% return in eight months?

For tips on relieving your money madness, check out Send in the Clowns, the stress management episode from WalletPop's video series, Loose Change: