cbmyers you should absorb some info here first before jumping into a gun.
First, it's very unlikely that you will find an effective, reliable gun of any type for $150. Even the $89 military surplus rifles at Big 5 will tip the scale at $150 once you've gotten a cleaning kit and a sufficient amount of ammo.
Second, you
need to practice to become familiar with the weapon and to be effective with it.
Third, a handgun is a compromise. A rifle or shotgun shoots a more effective round. True, a handgun is often handier indoors. Know its limits.
If you want a handgun you might find used a reliable pistol for $250 or a revolver for $200. Then add in the cost of ammo. Shoot at least 200 rounds through it and then shoot 200 more. The gun should work every time. You should be on target most of the time.
If you go with a shotgun, you can get a used one for $200 easily. Practice with it.
As to your revolver question, no, revolvers don't have
manual safeties. The reason for manual safeties in the first place was to decrease the chance of an accidental or negligent discharge due to the short, light pull of a single-action trigger. Revolvers do not have short, light triggers unless you cock then gun, at which point any accident is pure negligence.
Please review the safety rules. They are
paramount.
1: Keep the finger off the trigger until ready to shoot.
2: Treat all guns as if they are loaded.
3: Always point the muzzle in a safe direction.
4: Know your target and what is beyond it.
This discussion board is a great place. Stick around, you'll learn new things all the time
Hope I can help, and
Good luck!