Simple solution is not to try and buy recipes. The crafting system doesn't use them anymore.
If you have recipes previous to the crafting update, they will still work, hence the buttons remaining if you want to sell them (which you wouldn't do unless their ingredients can no longer be found).
The new crafting system has all the recipes built into the factory block. There's a button between the factory inventory and your personal inventory to select the needed recipe, and another button will then appear to show you the ingredients tree once a recipe is selected.