How could misspelling a word be profitable? When would you ever intentionally spell a word incorrectly?
When others are expecting it to be spelled correctly.
Still confused? Allow me to elaborate.
When millions of people are listing items for sale on Ebay, odds are that some of them can't spell very well. You can take advantage of that.
For example, suppose you are looking for a 1978 Camaro. There are hundreds of others searching Ebay for the same thing. There are usually at least a few that are misspelled in the listing as Cameros. Nobody sees those.
Therein lies the opportunity.
Whatever you are searching for, try obvious misspellings. If you find one, chances are you will not be bidding against very many other people, if any.