I've tried a few LTP and no sales. I'm a believer that art is price inelastic for the most part. There is just way too much art in every genre that are that are being given away.
IMO in order for LTP to work than it needs to pop up in your buyers face when they visit your site. If you're going to buy art than your not going to look for promotions on art, you're going to look for the art. Then if there's a promotion running that puts you higher in the buys mind as truly is a lucky find.
Another issue is the short time. By time shows up on the almost hidden LTP page here, than you're out of time and the page is full of expired offers.
Until I have time to write a popup of my LTP on my business site (non FAA) than think LTP are a waste of time.
-- mary ellen anderson