Kellan Lutz in SICK Lambo -- 'I Finally Got My Twilight Check'

Kellan Lutz wants everyone to know ... HE'S RICH, BIATCH!!! The "Twilight" star was rollin' around L.A. this weekend in what appears to be a Lamborghini Aventador ... which reportedly starts at $380,000. Not bad. With a big ol' grin on his face,…