The sensors/devices we provided for the $499 level Kickstarter backers aren't actually made by us, but we're considering offering them for sale until we launch our own sensors/devices.
They would be competitively priced for sure, but not a bargain, since we're not controlling the full cost.
If this is something that would be of interest, then please let us know and we'll see what we can do.
Looking at the Monoprice link you provided, those look like Vision sensors, so they should all be supported already, including the lock, as we have a sample of that.