I usually only spend about 10 dollars for a keychain light in a hardware store

You really don't need expensive lights for your keychain because often you can't change the batteries on them anyway. So, I usually don't spend more than about 10 dollars on a keychain light. By the way, I don't think you can take your Swiss army knives on planes. So, you have to pack them in your suitcase that you check with the airlines but you cannot walk on board with one in your pocket. they will usually just throw them away in the TSA line if you forget. I've lost at least 2 handyman knives and a couple of small Swiss Army knives that way over the years if I forget to take the mini-knives off my keychains.