This a such a low cost conversion for the kitchen and it keeps all your sponges out of the way. I also found that it works great in the master bath and provides a quick and easy hideaway for my toothbrush. We've also got the conversion kit to hide the trash can in one of the cabinets.
You can purchase these kits at Lowes for about $17.00. They have them at HomeDepot also but they're sold as individual plastic trays and Lowes comes 2 to a pack. 1 plastic try will fit in the faux drawer front in the master bath and if you got dual vanities you'll have one for each side and each packet comes with enough hardware to do two doors.