Just a heads up for the point about max capes, remember you can use the Anachronia base cape to hold one cape/perk for you at all times. Good candidates are Defence/Invention, since this lets you bind something else more useful to the cape like Slayer or Dungeoneering.
Slayer and Dungeoneering should go on your support cape, Invention should go on the anachronia stand, so you can combine it with any other skill cape perks during skilling and combat, and your Defense, constitution + a combat cape like ranged, strength or Master Necromancy Cape should go on your max cape.
if you get a lot of dungeoneering tokens from daily's, treasure hunter, etc--and you have a lot saved up, it can be worth spending 1,500,000 tokens on the gold accumulator and the slayer points to attach it to your tool belt, so that coins automatically get added to your pouch. This helps me mitigate the costs of ectoplasm when I'm doing K'rill. Also, if you have tons of springs, it's good to upgrade the spring cleaner and keep it in your inventory when you do slayer. It can auto-alch stuff, such as when you do gargoyles, it will auto-alch the rune stuff they drop w/out you picking it up, and that ends up saving you money.
The Springcleaner 2000+ doesn't need nature runes and can autoalch salvage, so it might also be worth using alongside the autoalchers if your getting them from PVM drops. It's only really worth it to alch mithril or better though if you're buying springs (use oddments instead) and 9001 works on noted drops too which is nice Making charges through divination also saves a bunch of money at pretty much any level, it's especially worth it if you're running any lower level versions of the machines in the guild or you need charges for your gear.
I remember when it was barely worth buying springs for rune drops, thats why I saved up over 35k of them through the years lol. You can make springs from the invention work bench now along with note paper
Another way to save some GP in the long run, is to make your own urns for DXP weekends. Not only does it save you 10k per urn over buying them, but having to do LESS to get MORE xp means you save that much more on supplies in the long run. Huge GP save right there.
Do your farm runs bro lol. Like damn I thought I was slacking. Plant power is pretty good and the low cost of low lvl seeds but high herb prices for incense sticks would be a way to make some gp