At Lowes the other day, someone recommended the TrimmerPlus Add-in
with Aero-flex head (AF720). This would fit my Troy bilt 4 cycle. It
takes 4 plastic blades that seem easy to swap out, but the cost may be
high depending on how quickly they break. A replacement pack of 16 is
$12. May be a lot cheaper to use one where I can cut my own string;
but on the other hand, it's probably going to be a royal pain to
replace the head to get things going.
Too bad there's no string trimmer attachment that simply comes with a
standard, non-bump head that takes individual lengths of string.