I will need Best OSRS Gold site about 75,000 Gold ore for 95-99, that's like 16M. When I market all bars that are going to be 28M, so I will make about 11-12M gain. I believe this to be right, it is only confusing when I had been considering it in my mind. And I was tired since it was just like 4:30AM. Also I did not add the potential amount of money gap if I had been to sell the Gold ore up front instead of use it to instruct Smithing, so that probably made it more confusing for me.
This is definitely not the best way but it's the way I do it and it works. It's also fairly cheap if you do it directly, at least I make money every excursion (not much but nevertheless gain ) even when I do not buy a Barrows item. Black dragonhide top/legs (I typically use what is left of my prayer points to kill Ahrim but if for some reason I have ran out of PP when I am battling Ah the Black dragonhide helps). Monkfish/Sharks/Swordfish, Super collection (I don't use a super set but if your combat stats are somewhat lower than mine you'll probably want )
Here is the Slayer dart method essentially: Take out DH first (do not forget to pray). Karil next (pray because he hits fast and hard, melee). Ahrims (use what is left of your own prayer + dragonhide and a melee weapon). Verac (most men and women pray here but I don't enjoy using Prayer pots so that I simply tank and utilize my food to heal). Guthan (hes a piece of cake, shouldn't give you much trouble). Torag (even simpler than Guthan). If you're thinking about why I take a Prayer potion it's if I get a DH tunnel, you always need to pray when fighting DH since he can hit pretty hard.
I normally receive a KC of 20ish, it will not help becoming Barrow items more frequently but it helps becoming buy RS gold more runes/racks etc..