Although I like chords and advice, the book is much simpler that video lessons, where Justin sometimes shows more advanced strumming and explains nuances of playing: for example for "Mad World" there is explanation of more advanced technique and intro playing, and for "House of Rising Sun" video contains explanation how to play it in style of "The Animals".
In other words, all of the guitar gods throughout music history played an instrument essentially like the one you own. It’s not like they have some kind of advantage, aside from their talent and experience. The same notes and chords they play are available on your guitar, and while it may take a lot of hard work on your part, you can play them too if you want to.
As a beginner, it is best to avoid making a pawn shop, flea market, or yard sale purchase unless you are shopping with somebody who has experience in purchasing a guitar. Having never purchased a guitar, you may not know what to look for in terms of damage or guitar quality. With that being said, a local music retail shop is your best bet. You may also shop online with a reputable company, although be sure to review the business’ return policy.