The best harp for kids will be the correct size, priced within your budget, and play well. There are many cheap and toy versions of harps available, but the best harp for kids will be the same quality as a professional, adult-sized harp but scaled down so that a child can easily play it. Not many brick and mortar music stores have harps for kids, so you will probably have to shop through online retailers or through catalogs to find a child-sized harp.
Before you begin shopping, think about how much you are willing to spend on a harp for kids. Many adults, when faced with a child who wants to learn to play a certain instrument, make the mistake of purchasing the cheapest instrument available. The argument is that the child may become bored with the instrument, and this keeps the adult from wasting too much money.
The problem with cheap instruments is that they are cheaply made. A harp for kids that is inexpensive is also typically harder to play and to keep in tune and has poor sound quality, which discourages even the most enthusiastic students. It is better to buy the best quality instrument you can afford.
If a high quality instrument is out of your budget, consider renting for the first three months, and then talk to the supplier about a monthly payment plan. Many retailers will deduct the cost of the previous month's rent from the total cost of the instrument if you decide to buy. A high quality lap harp is another option, since these instruments are much cheaper than their larger cousins, the lever harps.
A lap harp typically has 20-30 strings. It rests in the musician's lap while playing. Complex music can still be played on these instruments, but since they are small, the pitch of the strings is not very low. All strings must be tuned individually, so it is not possible to quickly change from one musical mode to the next. The advantage of this style is that it is very inexpensive and portable.
A lever harp has 30-48 strings and sits on the floor. The musician sits on a chair or low stool to play the harp. The lever harp has a greater range of sound than the lap harp with a good high and low end. Most lever harps can adjust the pitch one or two half steps, allowing the musician to play in various musical modes. They are shaped more like an orchestra harp, or full-sized harp, and students should have little trouble transitioning to a larger size when they outgrow the lever harp.
When you're shopping for a harp, the best way to determine quality is to play the instrument or to have someone play it for you. If you're not a harpist yourself, consider asking a harp teacher to accompany you and to help you decide on the best quality instrument. If nothing else, you can pluck the strings, listening for clear treble strings and full bass strings.
The wood should be just that: wood. Particle board or pressed wood is typically a sign of poor quality. There are some hybrids which use laminate or plywood, but the best harps for kids are made from woods like maple, birch, or spruce. Harps typically come in a variety of finishes, which have little effect on the sound.
Some harps are decorated with artistic carvings. Be careful that you are not overcome with the beauty of the instrument and forget to check it for its practical qualities. A lovely instrument must still play well and be within your budget. True enjoyment will be found not from looking at the instrument but from playing it, so a plain instrument with an excellent sound is better than a beautiful instrument with a mediocre sound.