I looked into ordering directly from Samtec and I seem to remember the price was quite acceptable (in quantity; the minimum order was pretty high). I don't remember the exact price but I put off ordering for a couple of reasons. I can do it now when I make the time. I have a resale license which probably helps companies take me a little more seriously than they would a hobbyist when I order directly instead of going through a distributor like Mouser; and then I also don't have to pay the sales tax when purchasing (but I have to pay it when I sell to someone in California). That eBay one is a good price except that the shipping is twice what the connectors cost.
Don't forget that we key the connector by plugging one of the holes in the socket to correspond to the pin that's removed from the pin header. This prevents plugging in backwards, and also prevents plugging in 3.3V parts in to a 5V pin header or vice versa..
I see now that the 3.3V CY15B104Q 512KB FRAM has the same package and pinout as the previously mentioned SPI flash memories, so that will work on the tiny boards too. Advantages are 100,000,000 times as many write cycles' endurance, and writes happen at bus speed, with no need to poll afterward to see if it's done writing, before proceeding with more operations. The disadvantage is the high price (hopefully that will be coming down), and that it does not come in as high of a density (hopefully it will be going up). Note that these are ferroelectric. They are not ferromagnetic, and will not be erased by a magnetic field.