Violins come in many different sizes and must be the correct size for the player. As a child grows they will need a larger violin.
In some places, violins are available for hire from music shops or music schools. Second-hand violins can be fine but it is wise to do some research before taking this option so you know what you are looking for. You would want to make sure that there are no cracks in the violin and that the bow screw moves smoothly in and out, and check the shape of the curve in the bow when the hair is loose. Like most things, you generally get what you pay for. For a beginner you don’t need a high quality violin but you do need one that works properly. Better quality violins are less likely to need repair work.
Another reason to get the best violin you can afford is for tone. You will be trying to reproduce the sound on the CD. This would have been recorded with a beautiful tone and on a good quality instrument. The nicer the sound your violin makes, the more you or your child will enjoy playing it and hopefully want to continue. Buy the best quality of sound you can afford.
You will have to listen to the sound of this violin every day and you will have a more pleasant time if it makes a nicer sound. Cheaper violins tend to have a tinnier, scratchier tone. Better quality violins tend to have a richer and more pleasant tone. You are more likely to enjoy playing and to feel like you are doing a good job if the violin is capable of producing a good tone.
A new student-grade violin will usually come as a kit containing the violin and bow, a hard case and rosin (which increases bow grip on the string). You will need all these things. Violins usually come with fine-tuners, but if not I suggest that you have these fitted before you start. You will probably also want a shoulder-rest. Violins will need occasional replacement strings and other maintenance.
For violins of 1/8 size or larger, you will probably want a shoulder rest to fit the violin. I suggest that smaller violins (1/32, 1/16 size and 1/10) just use a piece of foam. You can go into the music shops and see if you can try out some shoulder rests but generally I recommend the Viva La Musica Flex for violin sizes 1/8, ¼ and 1/2. The Kun shoulder rests are usually a good choice for violin sizes ½, ¾ and full size.
Some shoulder rests are collapsible making them more easily fit in the violin case. Some are adjustable which can cater for the next size up of violin. A well designed shoulder rest should fit well to the violin without constantly falling off, and also fit well to the player. Different shaped necks and shoulders can suit different shoulder rests.
Violins generally come with strings already on, but at some point a string will break or degrade or begin to sound dull and you will need to buy new strings. The three main types of strings are steel-core, synthetic-core or gut (I don’t recommend this last option). Steel-core strings are often put on student violins, especially school instruments which are rented out, because they tend to last longer and are cheaper. Synthetic core strings are generally considered to give a richer tone.
It is very important to keep the violin in tune. It is common for violinists to tune ‘by ear’ but this skill can take some time to master and a tuner can give you much more confidence at tuning the violin. If you are not confident that you can tune the violin by ear then I suggest you either get a chromatic tuner app on your phone or buy an electronic tuner that can live in the violin case. Browse for Tuning Apps on your phone (Android or Apple), there are a selection of them you can try to see what works best. For an electronic tuner to live in the violin case, one option is the D’Addario clip-on violin tuner.