Just about every Sanrenmu can be found for under $10USD. Yes, they are pretty good knives. All the tantrums by BF members declaring otherwise will not change that fact.
Perfectly good knives can be found around $10. The reason is that reasonably crafted knives are truly nothing special. Knives are extremely mature technology, pretty much among the oldest tools known to humanity. What we knife nuts pay more for is bragging rights, shiny man-baubles, and marginally better performance (If you're lucky.) Which is fine. Helps keep the economy fueled globally. I've come across plenty of knives that cost $10 or less, and are quite good tools. None have an expiration date, and will serve you well for a LONG TIME.