Farming is OSRS Gold the most enjoyable activities. You have many options to train and a variety of scenery. Also, it's not trained by repeating the same thing at the same location for hours, but rather allowing a lengthy break between runs of Farming to enjoy whatever you want.
Slamming Farming is like saying Slayer costs hundreds of millions. Take a look at the prices for Bandos Fury, Potions, Cannonballs and more. Farming has a huge variety of prices/xp ratios, it's very simple to find a solution that fits your budget. Because there's nothing other than the ability to learn and lots of farming, I don't have the desire to quickly gain XP. I prefer doing runs using Willow trees and Pineapple, which I actually make more than I take.
The most profitable herbs can earn a lot of money, and also provide a amount of XP. Profitable herbs are ones that aren't bottled in the Sorceress's Garden. To earn a living from farming I also collect and buy items that I can offer on GE.
This can include unfinished Broad bolts from Sumona, Battlestaffs from Naff, Sand from Bert, Flax from Geoffrey Pure Ess from Cromperty, seaweeds from Catherby general store, and occasionally chocolate from culinaromancer's chest (although it is more of a bother due to not being stackable).
With a Spirit Tree planted on Etceteria You can also increase your approval within your kingdom by watering the Dry Patch while farming the patches of bush. With the exception of specific minigames, the amount of XP you earn from farming is not determined per hour. It is based on real time. Although I don't do more than Buy Old School RuneScape Gold Tree run every day (or so it seems) it will increase my daily XP.