If you want a sharp knife that is pretty rugged, holds an edge, and is very light and very cheap you can't go wrong with an Opinel.
They also make a stainless version with sandvik steel which holds an edge well.
I prefer the carbon blade because it is super easy to sharpen. I have some crock sticks in one of those little 10 dollar lansky boxes. I put the sticks on 20 degrees and run the opinel up and down a few times and the knife becomes like surgically sharp. If you ever lose the edge and it won't come back you can use sandpaper and a mousepad to get it back if you screw up the geometry and then go back to the 20 degree crock sticks.
I carved on my knife a bit to make it easier to grab the blade and oiled the wood to darken it. Then you can put a patina on the blade using vinegar or something to help out with rust.
I have had quite a few of these and sometimes from the factory you need to adjust them a bit. You can pop the lock ring off with a pair of needle nose pliers or a small screw driver. You may have to tweak the ring by spreading it. You can loosen the knife or tighten it by adjusting the ring and by use and. I oil my blade with olive oil because I use it in food prep.
I have carried the number 6, 7, 8, 9, and 10 before and overall my preference would be for the number 8.
Regardless, these aren't combat or tactical but they are light, the steel is very good, and they are cheap.
