If you decide to buy a classical or Spanish guitar with nylon strings, you will find you have a choice of various sizes. Generally, there are three sizes:

1/2 (for children between 4 and 9 years of age)
3/4 (for children between 9 and 12 years of age)
4/4 (for teenagers and adults)

Besides the overall size, differences can be found in:

- string length
- neck size and
- body size (all of which are also determined by the overall size - see above).

As with all other products, prices of guitars can vary extremely. You can buy guitars from 50 USD to 5000 USD.Prices depend on the materials used for the guitar as well as the precision and craftsmanship involved in its production.
Guitars in the lower price range are usually machined, while the most expensive of guitars are uniquely made by hand.
A beginner shouldn't require a guitar that exceeds 150 USD in price. Music discount stores often stock guitars for beginners that offer great value for money.

Check the following to ensure you are buying a good and decent instrument:

• Check out the tuning machines. If you feel any pressure when turning the pegs or if they get stuck easily, don't buy the guitar.
• Check the position of the strings, i.e. the lower E-string. If the action (that is the gap between neck/fretboard and string) is more then 6 mm where the neck connects to the body of the guitar, don't buy the guitar.
• Strum the lower strings of the guitar. If they make a clinking sound, don't buy the guitar.
• Take a close look at the guitar. If you can see obvious faults in the finish, in the various parts, on the fret dividers (i.e. sharp edges) or even small cracks in the body, don't buy the guitar.
  

Generally, the above said ("Buying a Classical Guitar") also applies to the acoustic guitar. Additionally, you should check the sound system and its quality.

Listen to the amplified sound - you can do this best if you connect the guitar to a special amplifier for acoustic guitars. Compare the sound of several acoustic guitars and choose the one you like best.

Check the feedback when you play low bass tones and when you turn up the volume. It can later be very disappointing if you have to put up with nasty sounds on stage or during practice sessions.

Compare the volume between the various strings, especially if an equaliser is not part of the sound system that comes with the guitar.

See the paragraph on "Buying a Classical Guitar" - the same applies to buying an electric guitar. On top of that, an electric guitar has a lot more parts that you should check before making a decision to buy:

- number and quality of the pick ups
- vibrato arm
- fine tuning (also: "Floyd Rose")
- volume and tone controls

Whether these parts come with an electric guitar or not and what quality they are has an effect on the price of an electric guitar.
Because an electric guitar requires an amplifier in any case, both the instrument itself and technology play an equal part.

When you buy an electric guitar, you will have to buy an amplifier as well. It is always better to look at both and buy them together. A so-called Combo - i.e. a single, portable amplifier with an integrated speaker - is more than sufficient for a beginner.

The power output is a decisive factor for buying an amplifier. A small amplifier with a maximum of 25 W(att) is sufficient for home-use, while you will need an amplifier with more power when playing in a band.

It is generally better, if the amplifier comes with an integrated overdrive/distortion circuit. Valve guitar amplifiers are more expensive than those with transistors, but sound better distorted.