Below are some links to companies in Wake County, NC that rent, sell, or repair orchestral string instruments. Bow Time At School has established a business relationship with the Music & Arts stores at both the Cary location (919-854-0024) and the Triangle Town North Raleigh location (919-872-1601) to make it easy for you to get all the accessories you need at a 10% discounted price. But feel free to shop for what you need anywhere you want.
If you decide to shop at Music & Arts, ask for a "Bow Time Bundle" and specify the instrument (violin, viola, or cello). Included in all bundles is a light weight portable music stand, an Essential Elements Book 1, and a First Things First Book. The violin and viola bundles also include a shoulder rest, but you must know your child's instrument size to get the correct one. If you don't already have a properly sized instrument for your child that you can bring, then be sure to bring your child with you to the store. The cello bundle does not include a shoulder rest, but instead includes a "zeros" strap which prevents the end pin from slipping on the floor.
For instrument rentals or purchases, there are two stores in Wake County that you should consider: Triangle Strings or Music & Arts. Triangle Strings is located in Cary. Music & Arts will measure your child and provide the correct size (1/2, 3/4, or full). Triangle Strings, on the other hand, needs to know in advance what size your child needs, making the rental process a bit more tricky.
If you actually own the instrument and need a simple repair, consider Kagan.