Buy enough material to easily level up on your other rs gold skills. For example, if you want to train cooking, you can buy raw lobbies or swordies and cook them. You can train your magic even further buy enough runes to train that or you could train your runecrafting skill by buying rune essence and the talisman to the runes you want and get to work!
A lot of runescape players ask how to get the new dragonstone armour. The prestigious set of level 50 hybrid armour not only looks grand, but is universally useful regardless of the styles you and your opponent are using. Cheap runescape gold are everywhere, you can buy some to help you make the game more interesting.
Although you need to be a member to find the triskelion and loot the chest, the dragonstone armour is tradeable on the Grand Exchange, and usable by both free players and members.