I don't feel it is greedy to want more than $20 for your quilt, regardless of whether you purchased or were gifted the fabric. It is way too low. You also added batting, backing, and thread, plus wear and tear on your rotary blade and sewing needle. Not to mention your time. I would hesitate to sell a small wallhanging for that price.
Acquaintances often ask (practically demand) I make them a quilt (usually a bed size), expecting it to be a gift, or, if they offer to pay, it is what they would expect to pay discount store prices. I don't think it is insulting to be offered such a low price for a quilt, I believe it is ignorance. Most people do not think of quilting as a skilled craft or art form. They have no idea what is involved in the process of making a quilt. I am usually happy to educate those people.
I've learned to say I would love to make them a quilt once they purchase the materials. I explain how many yards I will need for both the front, back and binding at an average of $12, the cost of batting and an extra $20-25 for non reusable supplies such as thread, needles, basting spray, and a fresh cutting blade. If they are a good friend, I might offer to donate my time, otherwise I say we can negotiate the cost of labor once they choose a design. I then explain the how the simplest of designs will take (x) amount of hours, to cut, piece, baste, quilt, and bind, and how the amount of time could go up exponentially based on the design.
Occasionally run have someone who is bold enough to suggest I give them a quilt as a gift. I ask them if they would spend hundreds of dollars on a birthday gift for me? Would they spend 20-30 hours cleaning my house for free?
Once they have some understanding and appreciation of the time and money that goes into making a quilt, they usually change their mind in a hurry. In almost 30 years of quilting, only one person has taken me up on my offer. If it is a good friend, someone I actually want to give the quilt to, I would turn down their offer of money, and give them the quilt they like as a gift.