TAC-FORCE Spring Assisted Opening EMT EMS ORANGE Rescue Folding Pocket Knife - $6.74 shipped (Free S/H over $25)

Seemed like a good deal so I ordered 2. Neither blade would lock in the open position making them unsafe to use.

I've been really happy with a few different knives by the same manufacturer. One thing I would suggest is removing the screws one by one and dab some blue Loctite on them. I see people crying that screws fell out.... Take 10 minutes and secure them and they will never fail you.
The metal isn't the greatest, you'll have to sharpen it often. But they are amazing for the price. Good to have around as backups in case you lose your nicer knife. Keep one in the car.... You get the idea.

276 ratings on Amazon with an average of 4.5 as of 1/12/16 for a knife that is less than $10? Bought one and I'm not unhappy at all it's a decent enough of a knife for most anything.

You can't really expect great steel for under $10. But for a casual use utility knife these aren't bad. I have 6 or 7, about half of which are kept in small pouches in a few battle belt setups for self defense (or SHTF) scenarios. Spring assist works pretty damn well IMHO. Only one needed a couple dozen open/close actions to get the spring loosened up after arrival. I prefer the version with a hole in the proximal portion of the blade--great for index finger for further stabilization of the blade in a fighting situation. Nowadays I don't even go to the mailbox without protection, which often includes one of these in front pocket.