Word of advice. You stated you are a canvas. That's great. Really it is. Tattooing takes two people. The Tattoo artist and the Canvas. But as a canvas, you have some responsibility as well. Research and know what you are getting in to. Really try to understand what you can, should, and shouldn't say or do. The artist you went to acknowledged you were in a tough situation financially. Instead of telling you what his actual prices are or giving you an over the top, expensive quote to make you go away, he actually asked you, what you could do. Telling him 15 to 20 dollars was a slap in the face. I get it. You weren't trying to be an asshole. That was really what you could afford. Fine. But understand, that if you go to any reputable tattoo shop, you will get the same response. With the exception of 13 dollar and 20 dollar tattoo specials shop run on special holidays once in a blue moon, you will not find a tattoo at that price anywhere. And if you do, it isn't going to be a quality tattoo. $100 shoes at your local shoe shop vs 10 shoes from Walmart. You get what you pay for. No self respecting tattoo artist will spend his time and make an effort to give you a quality tattoo for 20.00. You want an inexpensive tattoo? Find a tattoo apprentice that is willing to practice on you. They will usually do it for free or charge you 20 bucks AND they'll try their best - most times.
Majority of tattoo minimums run $60.00 to $80.00. This is essentially the setup fee. Tattoos that fall under this price range are small simple infinity signs and semi-colon type stuff. If you do your homework and treat the Tattoo Artist with respect you might get a nice surprise. If you had done the homework, realized that 60-80 dollars was the norm, saved a little and told him that was what you could do. He might have said hey, I usually charge 120-150 but today, I'll hook you up. It happens. I've done it myself.
So in short. Yes, you didn't know but also, you are responsible as a canvas to do some research. It will benefit you in the long run.
Also - You referred to yourself as a canvas. That implies you want ART on your body and not just another tramp stamp. Don't rush to get tattoos. Save up if you have to and get something sweet. Be an awesome canvas. Put great art on yourself. Great art doesn't have to cost and arm and a leg. It just doesn't cost 20.00 bucks.