Why is coin used as a currency in WvW?
There are lots of gathering nodes in WvW. Have you tried using those to fund your PVP?
There are also lots of dynamic events in PVP, as long as you fight at an objective instead of in the middle of nowhere. Defending or attacking both provide rewards even if you don’t manage to take or keep your objective. While the money from these events isn’t huge, when I’ve played WvW it’s been enough for me to at least break even. The daily jump puzzle also gives you some rewards, though I don’t remember how easy those are to monetize.
For pure PvP we have sPvP. WvW is something in between.