Here’s one idea – how about something from the research on persuasion? People can be influenced to pay more for a product if they think that there aren’t many of the product available.

This comes from research done by Robert Cialdini. He called this “scarcity” and he stated that people will be willing to but a product if they think that the product is scarce (hard to find or might not be available for purchase after a short period of time).

You could do a study on this by first separating subjects randomly into two groups

Show both groups a picture of a product (say, a computer perhaps – but anything you think subjects would be interested in buying)

In the text of one ad, write something like “One a few left at this price!”

In the text of the other ad, simply leave out this text, or write something innocuous

The IV is the presence or absence of this scarcity information

The DV could be two things: a) how likely subjects would be to buy the product and b) how much they would be willing to pay for the product

To get this info, just give the subjects two Likert scales:
How likely would you be to buy this product? 1 – not at al likely to
buy ……………..10 – very likely to buy

and

How much would you be willing to pay for this product if you were willing to buy it: $50 $60 $70…..etc.

Do some searching on Cialdini and you’ll find that he identified a few other persuasion techniques. I’ll bet you could do some interesting research on any one of them.

Hope this helps!