I picked up one of those 4-sided/grit diamond blocks at Harbor Freight for around $20 and it's well worth it. Diamond sharpening tools should be use wet with water. As I mentioned above , cheap stainless blades will clog and ruin a good natural Arkansas or India stone in short order.

The better stainless knives are actually high carbon rust resistant steel , like 440C. They will show rust if left in the dishwater!