The easiest way to get your RSGP back is just to buy it back with RL cash. With very high quantities of gold, such as 500m+, you should probably sell it for IRL cash if you won't use it. But when you have NO gold, the fastest way to get some is just to buy it. Trust me, otherwise you will spend hours slaving for your money when you have none to work with (no merchanting, etc.)