The $340 per month doesn't tell you enough to know if it was a good deal or not. You need to know how long he will be paying to get the final cost of the car. $340/m for 1 yr is a good deal, but for 10yrs it's not so good.
Years ago when we were shopping for my wife's car I asked the salesman what is the bottom line, out the door price for a car. He asked my how much am I paying per month now and how much did I want to spend per month. I asked how much is the car. He ask how much can I spend per month. Suddenly I was arguing with a 2 year old. He didn't want to give me a bottom line number, he wanted to hide behind the "per month" number.
Getting something more affordable is always a good idea. I paid about $1,000-$1,200 for my daily driver 6 or 7 years ago. It doesn't owe me a dime. I can keep minimum insurance on it w/o thinking twice about it. If I go 1 year with out crashing it, than I'm saving money. Sure it needed brakes, tierod ends etc, but I'm still way ahead. I know enough to do most things myself. If you don't know you can get a book or watch youtube. Getting a car as old as mine might not save you money is you have to pay someone to work on it. My wife gets the "new" cars here. By new I mean a 2-5 year old trade in or lease return. I don't think I'll ever buy brand new. The hit is just too big. All these years later my car should still bring over $800. Try buying a new car and selling it 7 yrs from now for nearly the same price you paid.