I made t-shirt quilts for about 10 years. I hardly ever stabilized. Usually only with a very thin shirt. I had a plexiglass template for the shirts. I made all the squares 16". Cut the side sashing at 16", so if the shirt grew or shrank I could adjust it. I marked the rows of sashing as to where shirt and sashing should be. I used a low loft batting cause quilts aren't supposed to be fluffy. I carried all the standard colors for backing and sashing. If they wanted something different, I would tell them they could go get it and tell them how much to buy or if I bought it I would quote them retail price of the fabric and then hopefully I could get it with a coupon. I also did pretty much echo quilting on the shirts and a squiggle like pattern on the sashing. Never once did I have a complaint and mothers returned for other kids in the family. I would quote my low end and then tell them we can do THIS for this much more. Maybe suggest a lap robe for less money.
I hate to see you guys call some people cheap. Of course there will always be someone trying to get something for nothing, but in today's economy, some people can't afford to have a quilt made and are quite surprised at the cost.
My quilting machine was all hand guided and people were surprised that I didn't just turn on the computer and let 'er rip. So maybe some gentle education would help. I also would take payments, but they didn't get the quilt till it was paid for.
Also if you take credit cards, that helps some people afford the quilt. I still use the SQUARE.