To be honest, this really depends on how much you're willing to spend.
You can go as low as 150 and buy an Aftermath Kraken. Which are... Alright for what they are, but not amazing.
You could go straight up to a Classic Army, VFC, Real Sword or whatever really strikes your fancy in the higher up range.
Just depends really.
Its also easier to determine what real world gun you like most, then sift through brandnames and research after that.
Another good thing to do is get age verified if you're over the age of 18. Opens up a massive selection of guns to chose from, new and used.