There is a lot to consider in this kind of situation.
Money. At first blush, it might seem that the weapon should be a shotgun if money is a concern. They can be had for very little when compared to other types of good weapons, are common, powerful, and versatile. However, I posit that if she has only enough money available to get one defensive tool, it should be a handgun, not a shotgun or tazer. If she needs a gun, a tazer doesn't qualify. If she needs to carry a gun at some point, the shotgun is out. Even if she thinks she'll only have it at home, there may easily and feasibly come a time when it is important that she be armed outside the home. It's very practical for her one weapon to be a handgun in that kind of instance. If she bought a shotgun, then she doesn't have that flexibility.
Mobility/maneuverability. A pistol can lie under a pillow, or under a book, and be run by one hand. If she has kids at home, especially little ones, it is much easier to navigate a house with a terrified child with a handgun rather than a long gun. Some will say, "Oh, that's a terrible idea, she should never do that, what if she had to shoot?! The kid will be deaf." Deaf beats dead, and it is very feasible that a small child will need to be corralled and herded to a safe area in an emergency. Answering the door with a handgun behind your leg is much more discreet than with a Benelli or Remington or Mossberg pump.
Proficiency. At bad-breath to bedroom range, how much proficiency is really needed? We can write of anecdotes all night talking both sides of this, but the upshot of it is, most of the time, we need to hit minute of bad guy at 15 feet or less. There was a WWII soldier who was assigned a mission behind enemy lines on very short notice. He had never fired a handgun, but a handgun was the only firearm he could practically take for this infiltration mission. He was given 2hrs of instruction, familiarization, and firing experience with his handgun. He successfully completed his mission, and during his exfil, was forced to shoot his way out of a bad spot. That was the second time he had ever fired the weapon. He killed two German soldiers, made it home, and died in bed many years later, an old, old man.
What is more needed than a professional level of facility and proficiency with the weapon is the attitude and willingness to use it to survive. If she has that, whether it is motivated by a healthy dose of fear, protectiveness towards her children, or whatever, then get her into a good handgun, teach her to use it (or pay someone else to), and she will be fine. If she doesn't, then ... something she is willing to consider using or doing is better than nothing, I suppose.
, and she initially wanted to get her CCW license, but recently said she wanted to get a taser instead (guessing likely due to the cost of handguns and all the rigmarole that goes into getting a CCW license and such).
