go grab a 15$ harbor freight one, and a piece of old roof tin, and do a lil practicing. you can learn alot on a cheap gun.. whether you decide to stay with a sub 100$ gun.. or go to a nicer one like a DB.. the practice don't hurt.
many times you can find a DB knock off in the 20-30$ range at a chinese store.
I have a collection of different guns.
a syphon for primer and another for color.. plus a touch up with small can and butterfly on it. I also have a pressure pot and an hvlp.
none were over 60$.. and at least a couple were under 20$. I've painted dozens of tractgors and a few vehicles at this point.
neither paint, nor the gun was the limiting factor in quality of finish.
prep on the body is almost alays the bulk of it.
100$ a gallon paint out of a 400$ gun, on 5$ of prep work looks like a 2$ paint job.
30$ a gallon paint thru a 50$ gun, on 2 weeks of prep work can look real nice.