What's more effective -- "20-50% off" or use "up to 50% off?"
According to Marketing Experiments' Dr. Flint McLaughlin, whenever you use an X-Y range in your ad, most people will revert to the first number as the mean (average) standard. In other words, on a range of 35-50%, one will assume that 50% off is the exception, and most items are 35% off. (Slide 18 of PPC Live Optimization Clinic replay)
Based on his research and experience, Dr. McLaughlin suggests using "up to [your best discount]" to achieve higher click through.
Likewise, "over 50% off" is not as persuasive as "up to 75% off":
Of course with dollar-pricing, you would want to choose your lowest reference point - "from $70" rather than "$70-$150":
Beyond Click Through
Click through rate is not the be-all end-all of your PPC campaign. Conversion rates are also very important. When I worked at a shoe store we often had sales sections with "UP to 50% OFF!" signage. Despite ticketed prices, customers often assumed everything was 50% off. Many got very frustrated and felt cheated that only certain shoes were 50% off. Most were 20% off. These customers who have grown skeptical of "up to" offers may not respond to such ads as those who haven't been disappointed by them before.
I think in some cases, providing a range could attract more qualified clicks and reduce site abandonment and disappointment. Those that find 20% off an attractive offer will click through and may be pleasantly surprised with your 50% off deals, but won't demand them. Dr. McLaughlin says "clarity trumps persuasion," and I believe clarity also improves conversion.
Deterring Unqualified Buyers
Including the exact price of your item, even if it's not a bargain, is effective as it weeds out those who would bounce off your page when shown the price.
Just remember to triple and quadruple check your ad and landing page for consistency - the price promised in your ad must match the offer.
Don't Make Them Think
Numbers can be attention-grabbing, but also confusing. Don't turn your special offer into a question:
Punctuation is your friend. Say this sentence out loud: "Order $50 Free Ground Shipping"
If you've seen that Simpson's episode where lawyer Lionel Hutz adds ? , and ! to his business card, you know that "Works on contingency. No money down." can become "Works on contingency? No, money down!"
Better copy would read "Free Ground Shipping on Orders Over $50," "Spend $50, Get Free Shipping" or even "Free Shipping Over $50 Purchase."
Clarify what prices are for:
Is there a $2.97 charge to access the database? Is this a one time fee? Is this a typo? Do other sites charge this? Huh?
Don't make customer beg for the discount, or jot down some complicated code:
Your landing page should show the price or discount you promise. The customer should not have to mention or ask for anything. Affiliates, if you must use a coupon code, make it easy to remember like SUMMER and show it on the landing page.
Numbers can be effective, but as these examples show, you must consider the thought processes of the searcher before you write your copy.