The first and most important piece of advice is to reinvest your money back into your Runescape account. This means your levels should be the focus of your spending. Leveling up your character can bring in more money quicker and faster, so it is worth investing in Runescape. If you are someone who prefers Player vs Player (PvM) content, prayer, herb, law, and summoning should be your priority. Overloads, curses, soul split, ripper demons, and knives are all great investments for PvMers. The invention is also a great way to spend your Runscape GP, but it requires a wider variety of items to properly scale.

• Weapons
• Codexes
• Budget perks
• Tier 81 Defenders

Weapons

When it comes to weapons, it is important to upgrade your weapons first before upgrading your armor. DPS is king in Runescape, so it is important to get your weapons up to speed before sinking your GP into armor. 

Codexes

Investing in ability codexes is always a great decision. For magic users, the ability codex is a great addition to your inventory that will help you increase your efficiency in combat. If you're a Magic user and you're looking to get the most out of your spells, then you should definitely invest in the Great Concentrate Blastibility Codex. This ability is incredibly useful and will help you get more damage out of your spells. It also changes the regular Concentrate Blast ability into a stronger version, so you won't have to cancel it earlier on. Additionally, it makes the level 85 dual-wield weapons, which aren't that expensive, better than a tier 92 staff, two-handed version, which is way more expensive.

Budget perks

These are cheaper than investing in a new weapon or accessory and can make a huge difference in how you play. For example, perks like Crackling, Enhanced Devotion, and Relentless will give you more defense abilities, like Resonance, Reflect, and Barricade, without having a shield. This can save you money on food, as you won't have to eat as much. It will also help you get faster kill times and make more money.

Tier 81 Defenders

These cost nothing other than Engineering Tokens and time investment, and you can still use defense abilities without having a shield. They also give you access to dual-wield abilities, so you can get more DPS out of them. The Ancient Lantern, the Ancient Defender, and the Ancient Reprisal are all great options to consider, and you can get them by combining an Ancient Emblem with a Chaotic Splint.

Overall

There are plenty of ways to spend your GP in Runescape. Whether it is leveling up your character, buying specific items, or investing in ability codexes, you can make sure your money is being used in the best way possible.