you have several options to pay the upkeep of rng:
1. nm camping--hunt for your equipments and profit
2. silk hunting--easy gils and fame
3. woodwork--craft the arrows yourself
4. tanning--use the profits to buy stuff
5. alchemy--another profitable craft. Can also make flame and bullets
I personally do 1-3.
Arrows are very cheap until you get to horn and silver arrows. Woodwork will pay off in the long run tho. But you may end up sinking a lot of money to level it.
Fletching and arrowhead are very cheap, at least in my server. I wouldn't bother lvling those up.
You can use bow all the way if you want. Guns are good for pulling, 2hr emergencies, and ws. Otherwise, they are about even with bow if you factor in delay. They are only powerful when you get silver bullets (lvl 50). All other levels, guns aren't better. You also get elemental arrows to take advantage of mob's weakness. At lvl 71, if you can fork out 2-3 million for the best bow, guns aren't any better. There benefits of going the marksmenship route. You do deal the most one-time damage. And you can do status effects with xbow and have better hate control since you can control your damage output easier with xbow.
Crafting is your best bet, but only if you are commited to it and lvl it. Otherwise, it just becomes a money sink. You will probably better off buying from AH for your ammo in that case. If you do plan to take on crafting, you can start with arrowood log and turn them into arrowwood lbr. And sell them at AH and make about 1k profit while at it. Once you lvl a few, you can do bone arrows. After that, you do willow wands and maple sugar, but that's the one of the money sink period.
50k should get you past lvl 20.