Where do I start?

I've had a guitar for the last 3 years, but I've never really played on it. It broke about a year ago, but lately I've been wanting to play again, but need a reason to justify the $400 purchase. Where do I start so I learn properly, and have fun while doing it?

Try to find a beginner class or something. Otherwise, take lessons.

I'd recommend taking some lessons , you could learn from a book or video but a teacher can help you with technique . You'll learn quicker with a qualified teacher , search the phone book for music schools in your area .

nothing like a lesson.. Helps correct mistakes early..

For me, I picked one song and learnt it all the way through, rather than just learning bits of songs, and once I had that one down, others came easily.

+1 on a guitar class. Much cheaper than private lessons to start. Much of the first 2-3 months of beginning guitar is just building technique. At the beginning level, it can help to see other people struggling with the same obstacles as you too. Hopefully, the class will also help you develop some ideas about what you want in a private teacher before shelling out for the higher cost of private lessons.

See if your local community college offers guitar classes. If so, you can probably get college credit while you're still in high school.

Lessons are great, for many reasons. However, you might benefit from developing the practice of defining a goal and a means to reach it. I do this all the time, and I've been playing for a bazillion years. For example, I notice in my blues soloing, I like the sound of the note pattern F - Gb - F - Eb - C, in the C blues. However, I have a little trouble with that, since my 4th finger is weaker than I'd like it to be. So, my goal is to play that pattern smoothly and strongly. I then set a target of so many minutes, repetitions, 12-bar choruses, or whatever way I use to quantify my effort. Then, voila, a couple of weeks later, I play that pattern more spontaneously and with more nuance and inflection.

Maybe you stumble on an open D chord (not knowing you level, here). So, set a goal and strive towards that. Certainly, you will benefit from playing a D chord better. And that skill will transfer to other chords.

Or fingerpicking? String bends? Memorizing major scales?