choosing a gun is a highly personal thing, I find, what do you feel comfortable shooting and carrying for an entire day? can you find parts for it? can you find mags for it? can you find pouches for those mags?
Price should not be your primary concern, especially if you're going to be using it for a while.
A lot of people get hung up on smg vs long arm vs sniper rifle... these things mean very little in airsoft, they all operate based on the same mechanics, and an smg like a p90 can be made to shoot just as far and accurately as a full length m14. It comes down to what you want to haul, and what you want to be holding when the photo op comes.