Comment: For home defense, nothing beats a shotgun.

I have a Mossberg 6 shot 12 gauge riot gun I picked up for under $400 (but that was before the "gun salesman of the decade" was re-elected). It is pretty hard to miss with a riot gun, will disable or kill an intruder wearing heavy body armor, but will not likely penetrate the walls or ceiling of an apartment. I would not hesitate to take a shotgun up against an automatic weapon at ranges under 20-30 feet. Plus, the sound of pumping it will make even most diehard assailants relieve themselves. If I am "taking it on the road," I carry a "Chief's Special," hammerless revolver. It is easily concealable and "good to go". I keep an empty chamber as a safety, as it is easy to pull the trigger once, then squeeze off a round before an assailant knows what is happening. I would "waste a jacket" before taking a bullet by taking time to pull my weapon and a "Chief's Special" will easily fit in the pocket of a jacket or vest. Revolvers are easy to load and almost never jam. I cannot say that about any clip fed weapon I have ever used.
I have a 100 year old 32, but they also come in 22 and 38 caliber.
Whatever you hear about "stopping power," more Americans are killed
with 22s than any other round. In any event, gun stores with indoor ranges usually rent guns. Test fire a few before making a purchase.
You can buy a shotgun or rifle out of state, but you cannot buy a handgun that way. However, if your girlfriend is from a "gun friendly" state (say, Virginia), you can have her buy it. G. Gordon Liddy, a convicted felon who lost his Second Amendment rights, brags about the size of "his wife's gun collection".

The hardest part of "training" for firearms self defense is the willingness to kill without hesitation if you are certain you or a loved one is threatened. If you cannot get past that, save your money and hope for the best.

While I am not suggesting you break the law, may I mention in passing, you do not have a right if you need a permit.