What is the consensus on this for a Shield 9mm? Just put the spare mag in your pocket, use a belt holder or is there a decent (read cheap) pocket protector that can be had? I have seen some for $25 or more, thats not reasonable. Thanks.

Start here:

Carrying Shield with Extra Mag

Personally, I carry two spares in a kydex holder at 9:00.

Depends on how I'm dressed. Usually I carry a spare mag loose in my pocket.

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MSP - Retired

I use a multi-tool case on my belt. I have two of them but the Gerber works best for either the 10 round M&P40C mag or the 15 round full size mag.

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Former USN, Retired US Army

I used a eye glass holder on the belt then in the pocket and now just the mag in the pocket. I just about ran it through the wash machine the other day. Don

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USN Retired/VN VET
M&P X5

If you get a Remora holster they usually throw in a matching mag holder. You could either put it IWB or in pocket. Would be good for keeping pocket lint from getting into the mag as easily.

That was going to be my answer. Keeps it upright in your pocket for easy access, or canted at the angle of your preference IWB.

I just use a single leather mag holder that goes on my belt or in my back pocket for the 1911.

When not in leather, I carry 2 spare mags in an Uncle Mikes double pouch,OWB, about $15.
I've also carried single mags in old leather knife sheaths and a nylon Leatherman pouch I had laying around. New they can be had for probably $10 or less.
Good luck with your search.