I think most of the used leo-marked glock mags ($10) are gone, but the new leo-marked mags ($13) are in stock and they do ship quickly. Unmarked, new glock mags are $17. There is a $10 flat shipping cost so try to get everything in one order. I bought a few of the new leo-marked mags and they are metal-lined, marked, and new. No complaints.
They carry the standard mags, and they also have new mags that you can buy with the +2 baseplates already installed. I have big mitts, and I like to use these for the G27. However, if you just want the regular capacity (15) they go for 19.95, and the shipping is very reasonable.
I ordered four mags, a clip draw and some guide rods and the shipping was about $4. Plus, they ship the same day.