Then, I spent $13 on the Lansky Fold A Vee, and I've never been happier with a purchase.
It folds down small to fit in a gear pouch:

And opens up into a very effective V-angle sharpener, that can produce edges at 17 and 25 degrees:

Within about 5 minutes, I can get any of my knives to hair shaving sharp.

If you're looking for a way to keep your knives sharp, I highly recommend the Fold A Vee. It's compact, durable, easy to use, and made in the USA.