Idk, I just do what I love within the game and progress normally instead of vigorously grinding like a madman. I'm also premium 9 (480 days of sub bought when game released, master pack gave some time) just by buying costumes for Hongmoon Coin. As a result my main has like 580 AP only, but meh, no more is needed for any content :P Buy Blade and Soul Gold So atm I just pvp every season an achieve great ranks across every class, cashing in every 1.5 months on season rewards. I typically earn around 1.5k-2k gold if not more.
Beyond that just daily challenge a few times weekly. It's pretty easy to progress, it'll come naturally while you're having fun. If you think you need to strive for 800 AP, you're gonna be disappointed, because it'll be ages before any content requires that amount of dps. Heck, KR removed Hell Island to optimize it, so it won't be added to EU anytime soon.
Just have fun doing what you love within the game . If you can't keep up with current prices you're just bad. If you can't keep up with the new ones, don't play MMORPGs.Which costs? You literally need 450AP to clear any current 6man, 500 if you're REALLY bad Blade and Soul Gold .
I am currently 2-3 months in with being a sub but I played back when the game was in beta. And even as a sub, I can't keep up with the cost of my gear. I saved 100g and still ended up with only 24g left to spend. so this makes me very happy. ^^