Standard 2-plug will work fine in everything unless you end up in an Airbus (but you can get an adapter if that time comes). Google is a wonderful thing for shopping but that’s another thing about Bose, you really don’t see them going cheap anywhere (I believe Bose watches their authorized dealers pretty closely).
FYI I just saw them on Pacific Coast Avionics for $995 w/o Bluetooth which you don’t need.
Yeah I’ll agree that you won’t be able to find a new headset for less than the retail price. You might find a good deal on eBay with a used one, sometimes you can find them in good condition from people who started flying but decided that it wasn’t for them.
Also, I recommend you go with the non-Bluetooth version. Save yourself 100$, you won’t have much use for it during flight training or flight instruction.