When I was in school for diesel tech a few of us received cards for 50% off our first order at Sears. I applied for a Sears credit card and bought the largest Craftsmen set they had (ratchets, sockets, wrenches/ratcheting wrenches, various other tools, literally the works) with no interest rates, perhaps wherever you go may have the same sort of deal. Their lowest accepted payment is like $25 a month. Specialty tools you just buy as you need, and borrow from coworkers if you're desperate. Go on craigslist and buy a decent cabinet, and go to Harbor Freight for the rest. I know everyone really bags on their tools, but if you take care of them they'll last.. and even if they don't, most of their stuff has a lifetime warranty. I bought a DA, die grinder, air hammer and a few other air tools from them a few years ago and they all still work like new. I'd also highly suggest buying things like impact sockets and 1"+ wrenches from them. Their prices are impossible to beat, especially when you're just starting out.
And it really goes without saying, but stay away from the Snap-On and Mac tool trucks your first couple of years on the job. You might feel like a badass with the top-tier tools, but what you're paying for them really isn't worth it yet.
I thought harbor freight was like absolute trash? : (