Agreed, the whole double barreled shotgun is just a thing a select few companies market just because they know some new gun owners will buy one for $300+++... As for rifles and home defense, it is my personal opinion that a bolt action, AK, AR-15, Semi auto, any rifle really, is a bad home defense weapon. It is my personal opinion that any situation that a rifle's range is an advantage is a situation that won't go well for the rifle owner in court, and that a rifle in a home is a pointless waste of replacement drywall, windows, and bricks, if you take my meaning.
As for a pistol, if you want to CCW, a good compact Glock or anything similar could work as a carry and bedside gun, and pistols are fun to shoot. Ammo and the guns themselves are kind of pricey, according to my standards, anyway.
It is my personal opinion the #1 choice for a home defense gun is a basic Maverick/Mossberg/Remington/H&R/Savage/Weatherby/Stoeger/Ithaca/Benelli/Insert Brand Here pump, long or short barreled, depending on if you want to hunt, or a combo, and less than $300, if not less than $200. Any pump shotgun will work, based on budget and personal preference, so long as you know how to use it. Which means take it to the range, or your country backyard if you're lucky like me, and just blast some rotten fruit and old electronics and cardboard boxes and hunks of plywood and other junk with your choice of HD ammo every few days if possible, be it #4 Buck, 00 Buck, whatever. Practice with slugs as well, and mostly practice with Birdshot 'cuz it's cheap and has less recoil, but it still does fun things to old pumpkins.
Don't fall for expensive gimmick ammo or guns, like (IMO) pistol grip shotguns, or the whole coach gun thing. A pump is much, much better and cheaper. That's not to say that the (I'm assuming) Stoeger coachgun is a bad gun, but it is an overpriced marketing ploy for new HD gun owners, I believe.
"1st off, I'd look into a big, loud, friendly dog." I love dogs even more than I love guns.