I have heard how giving you are in so many respects of music schooling and I must say that I am impressed. You remind me of the pure idealism that we had in starting Apple. If I were young, with time, I'd likely offer to join and help you in your endeavours. Keep making people happy, not just in their own learning, but in the example you set for them.
Acoustic: I recommend a Yamaha solid top acoustic guitar. This guitar plays just as good as some that are many hundreds of dollars more expensive. It can be difficult to manufacture quality acoustics at low prices due to the importance of a solid top finish. When I was in college I scratched together the cash to buy a handmade acoustic guitar that was over $1,000 (I won’t mention the brand) but that guitar was nowhere near as good as this Yamaha.
Realistically, to start improving on guitar, you're going to need to set aside a bit of time to practice. Developing a daily routine is a good idea. Plan to spend at least 15 minutes daily practicing all you've learned will really help. At first, your fingers will be sore, but by playing daily, they'll toughen up, and in a short amount of time, they'll stop hurting. The following list should give you an idea of how to spend your practice time:
The web has a vast number of resources available for learning how to play guitar. You can learn how to play fancy scales, play songs, learn to solo, and much more. The trouble is, there just aren't many good guitar lessons available to someone looking to start playing guitar. These guitar lessons are designed for people who own (or have borrowed) a guitar, but don't yet know the first thing about playing it.
I bet that you’ve even tried other methods to figure it out. Spending hours on YouTube and google searching for some guitar method that will get you to the level you want, just to get bogged down in the TRUCKLOADS of seemingly unrelated material… Getting some friends that play guitar to show you something here and there, learning some songs off of tabs that are sometimes right and sometimes terribly, terribly wrong just to find that you’re stuck playing the same old things without knowing what to do next.
4.) Check the guitar’s string height by pressing down on the first, second, and third fret. You should be able to do so with minimal effort. Come to the 12th fret and press down. The distance from the top of fret to the bottom of the string should be no more than three times. If it is five times, the guitar may have a warped neck or too high of a bridge.