I mean compare what you do to what the competition does. Hypothetically, if the user may go to a competitor site, and see a cheaper price, without anyone having explaining the difference between the liners, he may just buy the cheaper one. Not realizing the lower price only seems lower, due to certain factors.

Don't approach web site design as the only liner business on the internet. Or that surfers immediately go to your site, and immediately decide to buy. Many surfers go to several sites, try to figure out alternatives, and compare apples to oranges. Try to design the site as if it is one among many the user will visit. Explain why seeing a cheaper price on another site does not mean the other site represents a bargain.

Value comes from the intersection of price and information -- create that information or risk having users decide based on the only thing available: price.