I tend to use what I have which may include older yardage that I have to piece, left overs from the quilt or new cotton sheets (I have a small hoard that I`ve collected over several years, all less than $10 a sheet). They all quilt equally well on my Juki and the ones I send to my LA èr have collected no complaints either. I would hate to go out and just buy yardage as most quilting fabric in my part of Southern Ontario is $15 a metre and the wide backings run between $15-$24 a metre which makes a backing for a King sized quilt expensive.