I dislike most of the well-known brands - they're too stiff.
C. Jenkins Company makes fabric sheets for photos that are soft as lawn cotton.
I buy the Miracle Fabric Sheets in White. 20 Irregulars, if available, cost $30 and just need some threads snipped.
Regulars are $20 for 10 sheeets
There's a discount for first time buyers.
http://www.cjenkinscompany.com