I also think that if you need more money to be able to buy some things, that maybe you could have a yard sale, sell things on Ebay or Craig's List and definitely ask for gift cards for birthday/Christmas.
If the general rule of thumb is when you don't have enough money is to 1. cut expenses or 2. increase income (or both).
Assuming you've already cut out food waste (many people throw a lot of food out of the fridge each week--that is money doing down the drain--food disposal), then increase the income.
Ask for gift cards to Joanns, or LQS, or other on-line sites, sell things on Craig's List or Ebay. Volunteer your time in exchange for fabric. Maybe someone has a bunch of fabric but could use a babysitter? Think creatively.
So, besides the coupons, the sales, the thrift stores, etc. try to find ways to come up with some money so you can spend it on fabric. Quit going out to eat (assuming you do)--eat frugally at home instead. Go vegetarian at least one day a week, don't throw food away, etc. Cutting back on the food budget can free up some money for hobbies, which, of course includes fabric! :)
Now talking DH into it might be a different story.
Just get the word out to those around that you would like their old fabric scraps, their cotton clothing (instead of donating to Goodwill, they could ask you first), and you can always ask at the local (non chain) thrift stores if they ever get clothing in that they can't sell due to holes, stains, etc.
I had great success with this when I wanted denim. I went to three thrift stores (not G & W Clothing or S & A Clothing :) but local stores) and they gladly saved things for me for three days. After three days I went back and had so many pairs of jeans that I had plenty to cut up to make several quilts...and that was from two or three thrift stores. I asked for the ones that they couldn't sell due to stains or holes.
Then, make what you can and be sure to say lots of thanks and give away quilts to those who are most generous to you. :) That way you help people see that you are indeed using what they are giving to you. Maybe you could even make a few charity quilts or baby quilts and let people know that you would like to do this. Working people often have a soft heart for charities and while they lack time, they will gladly help out someone who has no money but lots of time.