I'd say you can get about 200m RSGP. Try playerauctions for the easiest method or look around in selling GP section. As to items, probably better idea to buy cash because people take advantage of the price drops and sell items that are worth less than the public typically knows. For instance if santa GE price is 100m but it's only selling for 90 on the streets. Someone would charge $60 for that santa when that's really selling you 90m for $60, as opposed to 100m for $60.