Before determining what a good price for a beginner guitar is there are some questions that need answering first. Do you want an acoustic, electric or classical (nylon string) guitar? What sort of music do you envision playing? Are you serious about learning to play?
Anyway you choose to answer these questions, a guitar does not need to set you back all that much. You can get a decent one (new or used) for under two hundred dollars. Yamaha, for instance, makes very good guitars at very reasonable prices and they are very durable (mine is over twenty years old now!). And all the “big name” manufacturers (Fender, Guild, Gibson, etc.) also have “off-shoot” companies make very reasonable “cheaper” guitars. When I think of a good, reasonably priced acoustic guitar for a beginner, I almost always think of Yamahas. Mostly because I know a lot of people who still have theirs and they are still very playable.
Buying a new or used guitar can be an emotional ordeal, especially if you haven't the faintest idea of what you are looking for. This is why it's important to do a bit of thinking and investigating before even setting foot inside a music shop. It doesn't matter if it's going to be your first or fortieth guitar, take a moment to gather your thoughts. For a very helpful introduction to buying a guitar read the article The Rites of Spring. You might also benefit from reading several of the articles on the Guitar Noise Buying Equipment page.
Getting a Good Deal
There are very few objective points when it comes to the world of guitar, and the highest level of subjectivity is equipment.
A guitars worth and value is highly dependent to the one who plays it. Many can mention their thoughts on a piece of equipment, but you determine whether the guitar is “Good” or “Bad” upon what you favor or disapprove of in the guitar. The players thoughts overrules the reviewers thoughts. Reviews do help, but the final judgment should be made by the one who plays, not by the reviewers.
For those of you looking for reviews or thoughts on certain pieces of equipment - guitars, effects, amplifiers, visit Harmony-Central.
Harmony-central is a large collection of user reviews for a very large range of equipment for all forms of players. As a word of advice, look in the reviews for technical errors with the product, rather than entirely focusing on the type of sound it can produce, this may vary from player to player.