Stretched sprue is certainly cheap (FREE!), but does have downsides. It's going to sag and to taughten the lines you have to heat them. And if they don't taughten at the same rate, you're going to have some too taught and some too slack which pulls the mast out of alignment. The stretchy stuff (EZLine) costs more, but stretching it slightly when installing it keeps it taught when in place without distorting the masts. I will agree stretch sprue still has it's uses especially where you need to have a slack, or drooping, line. I've also tried fishing line, but it still has the same problems of stretched sprue. I find the stretchy stuff the fastest and easiest to use.