You just need to get caps somehow.. shoveling more shit or then go to HUB caravan lifting and get 200 caps and 50 exp.
Or mining and make something ammo/weapons and sell them.
You can also gather wood and junk and make 10mm pistols for sale (and xp), although you're better of simply making Brass Knuckles from junk.
That gives you more xp and probably more money as you only need to gather junk instead of junk and wood.
If you don't mind the small loss (30 caps) and have 40 science, go mining.
Make metal parts and gunpowder, from 1 metal parts and 6 gunpowder you can make 50 10mm JHP or 50 shotgun shells.
They sell for 9 each, which nets you 450 at Buster, Sha Enin, Mira and Dusty.
You also get 100 xp for crafting them and can craft 7 batches before your cooldown is too high to craft more.
I prefer this option over any other to make caps as it also gets you a nice amount of xp.
Especially at the lower levels, 700 xp is a lot.
As for NCR, which is where ReS. does his tagging, make a habit out of leaving at Vortis (northern part).
Don't trust anyone who's standing with a gun near the exit grid at NCR bazar.
Almost all of them are tent followers.
When entering the world map, wait a few seconds to check for followers.
If you have 1 or more followers, tag them red first (left click their name and click the angry face) before you kick them from your group.
On a side note, people offering "free taxi service" in NCR are often pk too.