I suck at this game. I have trouble with anything above normal due to reduced mney rates.
Can you help me once I'm back home?
Timur's got it down. The one that immediately comes to mind is the AA12, but there are other expensive weapons - the M32, the SCAR, etc. There are three tricks.
1. Start scavenging early (like, when there are 30-50 left, if you can handle it)
--Know all the ammo drop locations
--Check the ones farthest away from the trader first, then work your way back
The less ammo you have to buy, the more you save. Keep in mind that some perks (Support, Firebug, Demo, Xbow Sharp) need ammo more than others (Commando, Medic, BERSERKER)
2. Conserve ammo
--Aim for the head
--Switch to semi-auto if you can handle what's coming
--Try to get at least 2 ZEDs behind each shotgun blast
Blah blah, saving ammo.
3. Save money
--Dont buy armour until you have no other choice
--Try to get by on only one weapon and a pistol until you get what you need
The less you spend, the more you save. Careful though, being too frugal could kill you.
So yeah. You have both Timur's and my Steam IDs (top right, under Join Date, etc.), so come play a game with [one of] us.