Sewing - how much to charge/what's it worth?

I have been making a blanket/quilt for my brother for Christmas, with at least two more to follow for my friends (Three if possible). One of my roommates today asked if, when I am finished, I would be willing to make a T-shirt quilt for her. She has several T-shirts that she wants made into a quilt, but doesn’t sew herself and “nobody around here makes them.” She would of course have to buy the materials herself, and she offered to pay me.
I’ve never had anyone pay me for something I’ve made before, on top of which I don’t want to charge her what might be a fair price for the same work done for someone who is not a college student, and has a real job. But, I figure its a two to three day project plus doing the binding, so I’d like to make it at least a little worth my while, you know?
So I was wondering, what would you consider a fair price, considering I’m not going to fully quilt it (I’ll do the corner-tie method like I have on my own T-shirt quilt) and she’ll be providing all materials?

I found THESE on Etsy. Of course they probably include the shirts but you should be able to take an average and figure labor at around 60%.

That is a good way to get a price. I saw this on that site.

Pictured is a quilt made from the baby clothing of two brothers, who are now 3 and 4. Their mother loved their onesies and couldn’t part with them, so I turned them into a quilt. This quilt has been sold, I would be happy to sew a personalized one for you. It doesn’t have to be baby clothing, any t-shirts that are hard to give up would work.

Pricing for different sizes are listed below. The listing price of $100 is a downpayment. Finally prices are:

Baby Quilt 36x36 $125
Throw Size 48x60 $200
Twin Size 69x90 $250
Full Size 84x90 $300

Turn around time would be 4 weeks once I receive the tshirts.
These can also be personalized with embroidery.

You could figure how long it would take you and decide how much an hour you want to make.

That’s awesome that you make quilts. Personally I have never been able to charge a friend more than materials for anything I make or knit for them. Having said that people (not necessarily friends) ask my mother to knit for them all the time and she charges them materials + 50%.

best of luck

Thanks, everybody. I’ll see how many shirts she has and figure from there based on those selling quilts online.
She’s my roommate… we aren’t really friends. We were the leftovers last year when everyone else had already chosen roommates, and none of US got into any major battles (there was some drama with some of the other girls) so we stuck together this year. We hardly even see each other now that we have single bedrooms. So, while I wouldn’t let my friends or immediate relatives pay me, roommates or distant relatives, yes.