Leave it to marketers to create the tantalizing proposition of getting more for less when you buy their product.

Both the new Apple iPhone and Tide 2X are making similar claims.

For the iPhone, Apple says you get twice the speed for half the price. In fact, the first generation iPhone sold for $399, while the just released 3G version sells for $199. So far, so true.

One catch is that you have to sign a two year contract. But the sneakier one is this:

*MOUSE PRINT: The data plan for the new iPhone is $30 a month, compared to $20 a month for the old one. Over a 24 month period, you will be paying an additional $240 to AT&T for the phone, which, in essence makes it 10% more expensive than its predecessor — not half the price.

Now for Tide 2X. Procter & Gamble is turning back the clock to the 70s when liquid laundry detergents were concentrated. You only had to use 1/4 of a cup.  The “new” detergent in essence has half the water of the old one, so the new 50 ounce jug will do the same number of loads as the old 100 ounce one.

But in TV and print advertising, they say the new detergent is more powerful:

“Twice the stain fighting power in every drop” is the claim, and that might make you think it is stronger and better than competitors.

*MOUSE PRINT: The disclaimer indicates the comparison is to their non-concentrated former product. Fine. So while it’s literally true that every drop of new Tide has twice the power of the old one, since you only use half the amount , you are not likely to see dramatically cleaner laundry because the product is still diluted by a machine full of water. (Where “x” is the strength of the product, one-half times 2x still just equals x.)  

Of course, for treating stains directly from the bottle, there may be an advantage.