If you only plan to use a knife to open boxes or peel apples, a knife will do. If you want a knife with a little more flexibility, then you can recommend using a pocket knife with multiple blades.
After all, if you're looking for something that can solve as many different situations as possible, multi-tool is probably your best bet. You can purchase pocket knife online.
Do you want a locking knife or not? Locking blades are much safer to use because the blade locks in the open position, preventing the blade from folding in your hand during use. If you want this safety feature, you may have to use a single-edged knife as most knives and multi-blade tools do not have a locking mechanism.
Do you need to buy a pocket knife of one brand or another? You would definitely recommend sticking with the most popular brands like Case & Sons Cutlery, Spyderco, Buck Knives, Gerber Gear, Benchmade, and many others on the market today.
The main reason to stick with these well-known knife brands is that they all have a long history of making quality pocket knives and usually have a great backing.
How much should you pay for a pocket knife? While there really aren't any strict rules or guidelines to follow here, remember, you get what you pay for. With that in mind, you can usually get a decent pocket knife for $30 to $60.
There are cheaper knives out there, but the quality will likely drop with the price, and there are more expensive knives that sometimes come with a quality knife. Which is better, sometimes not.
Finding the best pocket knife is definitely a challenge with so many models today, so do your research and read lots of reviews before making a purchase.