Sorry, just bought an all-in-one printer though

They make a continuous inking system that you can easily refill, or replacement cartridges with a fill plug and self resetting chip (resets the "ink low" message).
With edge to edge printing on 4x6 it might be worth checking price stuff. Mine holds like 150 4x6 glossy paper. I suppose I could modify that for more.... printing a few hundred at a time would be as easy as selecting and hitting print.
$50 per 1000 is what your shooting for... depending on how many you are going to print it might be worth pricing a low end AIO or a mid range photo printer.