If you are camping with OSRS GP among waterfins, you'll in a position to obtain the charms needed for 74 before the quest is released. Be sure to use your spirit rubies, gemstones, etc. while you train! Also consider doing a quest like While Guthix Sleeps or Blood Runs Deep, both of which can give you a huge amount of experiences that you can use to summon.
I'd suggest Slayer. Slayer gives you access to many different creatures which all give you lots of money, often. From that point on which is your favorite monster to take down.
Blue Dragons are excellent moneyhowever, the disadvantage is that you need 70 agility for it to work. Before that, you could take out Black Demons, for money or perhaps. I would suggest that the appropriate equipment for you (considering your financial troubles) could include:
Melee- Guthan's Gear (Around 3M, but it takes away the need for food on a melee-able slayer task) Verac's Gear (1.5M It also comes with the option of praying) It's a ranger- I'd recommend Karil's set. I'm unsure of the price however. You can always go with Royal D'hide, which is available for purchase at a minimal cost. Mage- Ahrim's set costs 1M. It is possible to upgrade to Ganodermic for around 3M.
It is important to note that all Barrows sets (Ahrim, Dharok, Guthan, Karil, Torag and Verac) all offer identical bonuses. The abilities of their sets differ But of note are Dharok's gear, which allows you to hit higher while your health declines Guthan's gear that gives you healing for as long as you strike in the same way, and Verac's set, that offers a prayer bonus that other sets don't have, and offers a chance for you to cheap RuneScape gold hit more precisely through armour as well as prayer. Therefore, you could just buy the melee set that is the least expensive (Torag) and then use food.