By illegal gun, do you mean one with the serial number filed off? If that's what you mean it probably will be more expensive than whatever guns go for locally to you since that's a heavy prison sentence in a lot of countries. IF you just mean buying a gun without a background check or notary of sale but the serial number is present, it may cost around the same or less (depends on the person/dealer you're buying from). You're of course paying cash for everything. I live in North America, so I don't have personal experience where you are, but the most reliable way I know of if you don't have connections is basically what you alluded to:
1) Find a drug dealer (shouldn't be hard if you don't know anyone who uses, you can go up to homeless people and say you're looking for whatever, someone will let you know)
2) Buy from them a few times, harder drugs preferred (some college kid selling weed may not be of use)
3) After you've done a few deals and they know you, let them know you're looking to get hooked up with a gun
Throw them a few bills in needed, but most dealers I've known selling know someone or will sell one to you themselves, offer money for getting connected if needed. In terms of what you say to the gun dealer, nothing complex. It's not a gun store so unlikely they ask what you need it for, just say protection if they do. Let them know what type of gun you're looking for. Ammo you can buy online or without any background check, at least in NA but you can buy it from the dealer as well. Obviously, there are risks going around doing business with drug and gun dealers, but you're looking to buy a gun illegally so it is what it is. You could get scammed buying a defective gun or a dealer robbing you, but that's generally the reason to get to know the drug dealer first and seem like a reliable buyer, since it's not a good business model if they get their regular customers robbed. You can specify to the gun dealer you need to do the deal somewhere you can test the weapon, personally I wouldn't buy a used gun off market without being able to test it. Some guys may give you shit about it and say they don't do that, again you're call what you're personal limits are. Best advice I can give overall is if someone you're dealing with who seems unstable/overly sketchy then back out, you don't want to make deals with crackheads cause they're the ones who will try to fuck you (taking your money, selling a faulty weapon for quick cash, etc.). On the flip side, seem stable yourself. I mean this respectfully, but if you're a nervous wreck right now or scared of the situation, at least seem confident when you're dealing with them (i.e. say exactly what you want to purchase, don't seem sketchy or nervous yourself, make a deal and be done they don't need your life story).
