Saradomin swords are better OSRS GP than str, however it's price is 4m-5m, and you aren't able to afford it. For the sheild slot, (unless you are tanking for example, or fighting drags) Dragon defenders are the most effective. It's not tradeable however, and it requires you to kill cyclopes in the top floor in the guild of warriors to acquire the dragon defender..
If you go in after collecting tokens, head to the cyclopes and, on "all tokens" mode take on them.. When u kill them, it is possible that one of them drops is a defender of the nxt level.. For instance, if you kill a cyclops , without hitting any defense, it may drop the bronze defender..
When handling bronze, they drop iron, and then iron, and so on. However, defenders are extremely rare drops, so going from no defender dragon defender will probably require a couple of hours, plus the time it takes to collect any tokens. If you're going for a boss position or work in a position where you'll be taking a lot of damage, you'll require the defense fs (8.5mil) But it's not ideal imo.
I know most of those Agility- Take the Barbarian course until you reach level 52. Then go to an outdoor course. Food should consist of three levels of agility boosting pies, along with some tuna. Only bring a spotted/spottier cape. Another option is fishing for flying trout, salmon and sturgeon.
Thieving - I think the Thieve's Guild is the old school runescape gold way to go, but I don't have 70 thieving, so I'm not sure. Slayer- Do Smoking Kills quest if you're not doing it already. Make use of your top or second most advanced Slayer master you can however, always use the top each five-day task to earn more points for slaying.