Personally...I find that the roughly $4 or $5 that it cost me for 100 of the yellow anchor "snap caps" is money well spent. As opposed to spent brass, the anchors can be snapped hundreds of times, because the plastic does not easily deform, and can survive hundreds of firing pin strikes. Also, they will feed from magazines (most of the time) so I can introduce a "misfire" into the equation for a student, and can observe any flinch or anticipation, which is not possible with spent brass. Finally...it's convenient to peek into the chamber, and see the bright yellow anchor as an obvious indication of status...whereas peeking into the chamber and seeing a brass case, well...you must assume it's a live round, and eject it to verify the status.

Considering that these 100 anchors were purchased 10 or 12 years ago...and that I've given a few out to friends, almost all of my .22s live with them in their chambers, and I still have 40 or so of them in the little box...I'd say it's $4 or $5 well spent. I guess if that's too much of an expense, then the spent brass cases are the next best option.