Normally, PSone screens in the UK go for about £20-£40 each plus about £5 postage - the ebay seller in question is selling at the cheaper end of this bracket. $20-$30 plus postage in the USA for an NTSC screen is a good price.
BTW, FYI - the seller posted this to me (I gave her my Wordpress site link so she knew about why I use the screens, and a link to this topic):
sarah wrote:I like the Into Play

- as for official PS1 screens i probably have 100+ sitting about atm, they are in various conditions, some as new with the screens protectors, some without and a few light scratches and some with a bit more damage to the case and some which have broken hinges.
Kind regards,
Sarah.
Broken hinges and scratched screens don't matter when the screens will be ripped open anyway, as long as the LCD screen itself is scratch free, no marks or bumps or bubbles on it. If you buy any PSone screens, always worth sending a note to the seller to check this...