A course stone is what you want to restore the tip. A good diamond stone will work on any type of steel, and is a good purchase. I'm not familiar with the Lansky diamond stones, but I suspect they will get the job done and it sounds like a very good price. I have a couple of large DMT bench stones myself, but they are considerably more expensive than that Lansky set.
If the knife is not made of a really high wear resistance steel, then silicon carbide (wet-dry, black in color) sandpaper will work well and is available in a wide range of grits. That is the cheapest way to get started- you just lay down a sheet on a hard flat surface that you've wetted and the paper will stick to it, then you can use the sandpaper like a stone. 220 grit is probably what I would start with. You can get up to 2500 grit.
Do you have any experience sharpening? Also, is your balisong double-edged? Normally I would restore minor tip damage by working down the spine, but if it's double edged then there is no spine. You'll have to work on the bevel from both sides of the tip. The tricky part is to keep the belly curves the same shape as before (or as close as you can). The smaller the chip the easier this will be.