Sellers Can Ask for an Appraisal, Too
There are certain situations in which a home seller might want to order their own appraisal. For example, it's not always clear at what price a home should be listed. You might meet with several real estate agents, each with very different suggestions for the initial asking price. If you set it too low, you'll make less on the sale than you could have, but if you set it too high, you'll scare off potential buyers.
In that situation, it's perfectly reasonable to pay the $300 to $400 for an independent appraisal to find the most accurate market value of the home and set the price accordingly. Just know that the lender is still going to want their own appraisal, so your appraiser's assessment isn't the final word.