Is it less than $100 or under $100? Is it more than $100 or is it over $100?

Question

I am building a web site and need to clarify something for a non-U.S. customer. It's whether to use "less than/more than" or "under/over".

• items less than $100.00
• items from $100.00 to $500.00
• items more than $500.00

Or should it be

• items under $100.00
• items from $100.00 to $500.00
• items over $500.00

Is there one that is blatantly wrong?

Answer 1

All of your variants are grammatically correct, and will be easily understood by native English speakers. The less than X is idiomatically identical to under X when referring to monetary amounts, as is more than X with over X.

However, if your audience is international, you might prefer to say items costing less than X or items costing more than X simply to avoid any possibility of confusion or ambiguity.