IMHO, and I have been doing silver Strikes for the last 20 years.
It depends on
1) Are you playing with red/blue caps in the machines? That decreases the cost of a clad strike
2) How much money are you willing to "risk" or spend?.
If you only want one or two as "collector's items", you are at the whim of your luck. Could cost you $1.50 or $2.25 for two or three (three in a row is the most I've ever won), or you could go $50 and not get one.
If you are prepared to go for the "long haul", like during a Silver Strike event, when the object is to get 30 or 60 clads, then your "cost" per strike will probably be less.
Using red caps as $30 and Blue caps as $20, I would estimate that the overall cost over the years has been $12.00-$15.00 per clad strike. Note that I RARELY play at QQQQ unless there are red/blue caps in the machine.