As a level 95 player, I've had all available machines for a while. I haven't had coin problems since around level 60 or so and for a couple of months I've had more coins than I can spend.
Within my nh I sell everything at default or lower. When selling publicly in the RSS I always, always sell at default price, regardless of what it is, mainly because of two reasons:
1. I don't need more coins.
2. I remember how insanely fun it was as a low level player (when coins were in shortage) to find cheap stuff in the RSS.
But why do so many high level players, who probably are in i similar in game financial situation as myself, sell everything at max price?




