I don't need many and SIGARMS has a minimum order fee. Who online has them in stock, or anyone here have 4 they want to sell/trade?

Why don't you make 'm yourself.
I bought one of those rubber "scrapers" you use to fill the joints when doing tiling and cut out pads the size of my magfloorplates.
Degreased the floorplates and attached them with industrial strength doublesided tape.
Costed me about $3 or so, did already 4 mags and I still have "material" left for another 4 mags.

Here's a pic with the endresult.
Should the link not work, drop me a line and I'll send them off-list.