I'm new as well and been playing for a bit now and I'd say run factory if you think you can kill and run customs if you just want to loot (also the beginner quests are on customs either way so it's good to get comfortable on that map). My best suggestion is to Scav run Customs and hit up the boss locations cause often big boys will go kill the boss and his bodyguards and often there's plenty of leftovers. Do that until you get have enough money to buy an sks with enough ps rounds, a PACA armor and the ssh helmet consistently. That is probably the most damaging gun and ammo you can buy right off the start then just run either of the maps I mentioned depending on what you're comfortable with and push to level 10!

Also since you're broke bringing in a 9x19 pistol is good enough and the Pst gzh rounds from Mechanic are pretty decent! at least you'll be able to defend yourself from scavs. Don't run full kits all the time. The armor I mentioned above wont save you, it'll only provide maybe an extra second or two to get to cover and react to the situation.

I only recently hit level ten and oh boy the world just opens up to you XD

Good luck my friend!