Build up your arsenal with real fire power, cheaply and effectively:
No Firearm is “one size fits all”.
Every type of gun has a purpose.
Different Purposes of having a Firearm:

Home Defense
Personal or Self Defense
Hunting / Utilitarian
Sport

What I look for in a firearm:

Reliable
Reputable Manufacturer
Something that will last
Ballistics are good for the purpose
It is tactically superior
Ammunition costs or availability

Shotguns are a Great First Firearm

Shotguns are cheap and reliable, used ones are even cheaper.
Pellets Spread and if you are using #2-4 Buckshot, it is a great home defense round
Chances of impact damage on your target is higher
Chances of shooting into another room is lower
Home defense rounds are available.
Basic Shotgun types worth purchasing:

410
20 Gauge
12 Gauge
10 Gauge
12 Gauge

12 Gauge Shotgun
Saiga 12 Shotgun. Credit to Wikimedia.org
12 Ga pump is my favorite for hunting
20 Gauge Shotgun
20 gauge double barrel shotgun
20 Ga youth model is

Lightweight
easy to maneuver
can be modified with different stocks, like a collapsible one.

I don’t do it, but most can have tactical rails placed on them as well
If I had to choose, I would choose 20 Ga
Same shot sizes in the firearms, 20 gauge fits fewer pellets
 
 
 
 
HandGuns can also be a great first firearm

Handguns are easy to carry, easy to store and great for personal defense.
Basic Handgun types worth purchasing

.45 Cal
.40 Cal
9mm
.357 magnum
22LR

The .45, .40, 9mm, and .357 are the most common police rounds
.357 Magnum shoots .38 Special which is commonly available, but not really sought after during ammo shortages.
.44 Mag is generally available as well
Rifles are great for targets
Credit to Wikipedia.org
I personally think that a shotgun and handgun should be considered before a rifle.
Rifle types that are worth purchasing

30-06
30-30
7mm
Ruger 10/22
AR-15 or AK-47
300 Magnum

30-06
Great for White Tail deer
Awesome round, and is the base for many other rounds
Was overly expensive during the shortage, but still available.

123: Firearm List for Beginners from Kenneth Jensen
30-30
Was the go-to-round before the 30-06
Was available, is generally cheap
I recommend looking at a Marlin lever-action
7mm
7mm Magnum or 7mm Mauser are both great deer rifles.
300
“Big Game” rounds… the real stuff
Go with a 300 Win-Mag or 300 Weatherby
Expensive Rounds, but usually available, and you won’t shoot many
Shooting is expensive and taxing on the shoulder
Carbine
Carbine

Ruger Mini-14 (5.56 mm) or Mini-30 (7.62×39)
Winchester 94 Trapper (.357), Puma 92 (.357/.38 or .44 Mag), Marlin 1894
Go with the Puma 92, it seems to be cheaper than the others, and is known as a very reliable gun.
M1 Carbine (.30) – Civilian Version
Hi-Point (9mm, .40 S&W, .45 ACP)
The obvious AR Platforms

Stock up on what everyone else is ignoring as far as ammo goes.

12 Ga, 20 Ga
30-30
.357 with .38 Special Backup
8mm Mauser

You must choose the firearm that is best for you: