All strike indicators have their pros and cons. Several are a pain to cast. Yarn indicators cast well but slip.
"New Zealand" yarn indicators don't slip, but $15 for a starter kit? I don't begrudge a guy making a buck with a great idea, but I can't afford foofaraw at prices like that. I found this forum post some time back about
how to make your own New Zealand style strike indicators, for around $5. The inital purchase of "consumables" will last you (and your kids, buddies) a lifetime.
Items needed: #1 -
Knit-Picker, $2.50 in the sewing department; #2 - roll of
2mm Pony Bead Lacing, $2.50; #3 - any water repellent yarn of suitable size/color (I've collected free skeins of Dazzleaire Antron knitting yarn and polypropylene macramé yarn for tying flies in various colors); #4 - an old clear felt pen cap to put over the handle end of the knit picker for yarn storage and to clip everything into a convenient pocket. I guess you could drill a hole through the knit picker handle to thread some heavy mono through and make a loop for clipping onto your vest/pack/what have you.
It's very easy to use. Preload ahead of time by cutting 3 to 5 pieces of the tubing about 1/8" to 1/4" long and threading onto the Knit Picker. Then, when on the stream, hook your leader/tippet with the Knit Picker at the spot you want your indicator, close the latch, and slide one of the tubing collars over the latch onto the tippet making a loop. Remove the Knit Picker and place a few strands of unbraided and combed out yarn centered lengthwise inside the loop then slide the collar up to secure the yarn in place. (The StrikeIndicator website linked to above has pictures demonstrating how to do it.)
When I'm done I can usually remove the yarn to put back into the storage cap, and put the tubing collar back onto the knit picker for reuse.