Its alot easier to find then you think, especially if you are in a fairly populated city. The hard part is throwing on your boots and deciding to put yourself out in harm's way to find it. And if you have never done it, now you gotta learn how to use it and get the supplies. You might even mess it up your first few times.
In the homeless areas, or just sketchy areas, you can sniff out what you need. I dont like hanging around the areas, but that's where the free food and shelter is... Maybe you gotta be a bit street smart...but its these dealers job to get that money out your wallet. Dealers are pretty easy to spot, or you go to a head you and offer them $20 bucks to get a fix. That's if you haven't already had somebody come up to you and offer it after wandering around the area with your hood up and hands in your pocket. Dont do it though. You never know what you're getting.
If I took everything that has been offered to me out of the blue in the last month alone, i could open a pharmacy.