My choices of fabric start at the op shops. Primarily Savers because it is close by. A couple of reasons for this, I like to re use and recycle as much as possible, It helps another charity at the same time, I have a good relationship with them. Get to know your local op shop and see what happens.
I am writing this piece to help you think about the fabric possibilities out there, I use sheeting, quilt covers and even cotton curtains. I take my time in there and turn everything inside out before I buy to make sure that what I get I can use Check the labels too to make sure that it is indeed cotton For linings I like to add colour, even if it is a pop of colour, even floral. Nothing wrong with a bit of femininity in the laundry.
Stripes, plain, patterned It all adds to the surprise.
For the outer covers I look for pop culture, cartoons, movies Kids prints are great as the bags are often given to their children when they go home. and generic fabrics. Lots of bright pops of colour. Here are some examples.and some more
All this lot of fabrics I bought from Savers yesterday.
So this is it all, Cut up and ready to sew, 114 pairs of fabric equals 57 bags ready to sew.