tbh it used to be a lot easier to grind gigas cause the parts and items used to be worth almost triple what they are now, so everyone grinded 172 and sold the items for gigas. It was hard work, but it was possible to grind 50m in just a few days. But nowadays we have no good way of grinding money until Allie switches Elektra parts to being worth gigas, cause 172 is a waste of time since it gives barely any exp compared to 258.
I personally paid for 2 guild expansions, 3 co-leader slots, and the exp buff all out of my own pocket. But if you can't afford the guild stuff, it really doesn't affect anything. The whole point is to have something that is a giga burn, to remove some of the gigas from the game, so unfortunately, I doubt the price will be lowered. But like I said, it really doesn't affect you a whole lot...