Magic will be a big rs money maker. High alching will bring you gp and experience, as not many can high alch they will give you a slight profit for alching their items.
Are some things you will be able to high alch, early on the bows.
Combat magic, getting fire strikes to take down black demons may reap you some good rewards, such as rune armor or weps. They can be safe spotted so they will be better to kill then lesser demons and you can know it is easy to get cheap rs gold.
Magic will also be pretty powerful in the wilderness early on, teamed up with a few more mages and you could be rather deadly. But the rewards may be very slim in the beggining.