With the 1.9 update Gapples can't be crafted now. This caused a huge uproar in the gold prices pre-1.9. Now that the dust has settled and we haven't been able to craft them in a while... what's the outcome? I pretty much took a hiatus from EMC shortly after 1.9 due to getting addicted to one of my new games and haven't been around to see the changes. I have been summed up- mending books made it so that getting into enchanted items will fetch you less consistent customers, killed the value of enchanting books, destroyed the demand for gold and gold prices. I haven't heard anything about the Gapples though. I'm kinda curious.
So many were hoarded, and their use is so marginal, that I doubt you will get much out of them. At least for a while. Honestly you get the same or better effects with potions, aside from the brief regen surge. They are super handy on a pvp server, but this is EMC lol. They are mostly a curiosity/collector's item now, and they aren't that rare. The gold content on an enchanted apple is worth around 700-850 depending on the server. Azoundria is selling them for 2389 but idk if anyone is buying. His prices are on the high side usually. Skarecboi is selling them for 10k. He doesn't actually want to part with them.