I'm setting a bit of a challenge for myself. It's too easy to get weapons and ammo from vendors, so I've come up with a challenge that makes good use of the crafting system and non-combat skills:

No buying weapons or ammo from any merchants, even caravaneers. Only looted or crafted weapons may be used. I may, however, buy crafting components.

No paying for weapon repairs. If it can't be repaired by the Lone Wanderer, it won't be repaired at all.

Armour may be repaired by vendors.

So far, my LW is doing pretty well, after a rocky start. Being a goody two-shoes, she tried to get out of trouble by surrendering her weapons to the Vault 101 Overseer, who then attacked her, forcing her to flee, lock herself in the Overseer's office and escape the Vault. Initially lacking anything stronger than a baseball bat, she acquired some decent hardware from Vault 106 and the Super-Duper Mart before finally buying schematics from Moira and slapping together some homemade weaponry to take to Minefield.

This is actually my normal way of playing. I buy nothing from merchants. Some characters do not even sell to merchants. I like to play characters who stay out in the wilderness. Conversely, one spent the entire game inside DC. These characters do not have the opportunity to visit merchants even if they wanted to.

Everything is scrounged in my games. All of my characters do their own repairs. Playing this way lends a desperate, survival-ish feel that blends well with the game world. For me, a self-reliant Lone Wanderer struggling to survive in a desolate environment fits the atmosphere of the game perfectly.

Nice. The only reason I made an exception for armour is because I want mine to keep wearing the armoured V101 jumpsuit, which is hard to find repair materials for. If it breaks in the middle of combat, I swap it out for some armour until I get back to a repair shop. She does live in Megaton, though.

Nice. I have had a couple crafted weapons only characters. Plus baseball bat and bob gun, too.

I came up with an interesting (and rather gross) variant of the Rock-It Launcher: The Gore Gun. Basically it's a Rock-It loaded with mutilated organs looted from Super Mutant Gore Bags. Disgusting, but effective. If anyone wants to mod that into a unique item in the PC version of FO3 or FO4, be my guest.