I bought these from this site:
http://football.epicsports.com/prod/21235/martin-football-3-compartment-wrist-coach.htmlLess than $4 per for the black, plus shipping (I think I paid $9 to ship a dozen).
They've lasted 3 seasons so far with no noticeable degradation. I've had the single window versions for longer - 5-6-7 years - and they are still just fine as well. I think I picked up the single pane ones on Ebay, about the same price.
I wash and dry them every week, no issues running through the dryer (I don't use a high heat setting) except the plastic windows would stick to the metal dryer drum. So last year I bought a mesh lingerie washing bag and that's worked great. I believe Coach Cisar has mentioned he doesn't put through the dryer - I tried that but had a heck of a time getting them dry, took forever.
If I have a complaint, it's that the velcro on the window flap is too good - some of the kids can struggle opening it during the game. Then again, at least it's not flapping around during the play...
I use an excel spreadsheet for the inserts (8 inserts per page). I bought a cheap hot laminating machine and do them by the page. I am able to then cut them to size and they stay reasonably water proof. I played around with the size of the columns and rows on the excel sheet until I got them to fit the window.
I personally list a brief play assignment and sort of list the play. For example, if I'm running Trojan Sweep Right to my HB, the RTE will see "Trojan R - Down/On/LB", the G's will see "Trojan R - pull RIGHT alley", the HB's says "28 Trojan - follow blockers", and the QB "28 Trojan - hand-off". All are the things we've gone over in practice. However, I DO NOT practice with the wrist coaches. The kids learn and run the plays in practice based on the play call. To me, that allows me to avoid them getting tunnel vision where they don't know what's going on.
It's worked well for me. I'd rather just list the play call, but with a small roster I have kids playing multiple positions, and this has made it much easier to do that. I use the 3 panes for positions. That does limit me to the plays that will fit on one insert.