Elastic - cheap price.

http://www.ebay.com/sch/items/?_nkw=FOE+by+the+yard&_sacat=&_ex_kw=&_mPrRngCbx=1&_udlo=&_udhi=&_sop=12&_fpos=&_fspt=1&_sadis=&LH_CAds=

http://www.sunshineshoppesupply.com/Beading_Supplies_s/1859.htm