What kind of musical equipment do you already own at your home?
Sound sources: voice/instrument, PC/ laptop, iPad/tablet, iPhone, cell phone, Bluetooth speakers and headphones, CD/DVD/Blue-ray players, vinyl/LP/record player or turntable, cassette tape players or even reel-to-reel tape players.
The most common recorded music media you may have access to depends on your background and household equipment.
There are online sources such as streaming services (Apple, Spotify, Soundcloud etc) as well as digital files called .mp3/.wav/.flac formats. Online recorded music libraries also offer access to historical recordings and musical archives - more so than streaming services might offer. Records and tapes provide a wealth of music that you get to keep.
What you'll need if you're taking piano:
An acoustic piano is best - start with an upright acoustic that isn't very old, has a recognizable name like Yamaha or Kawai, is in very good playable condition and has been recently tuned. If a piano is out of the question, please consider a stage piano and amplifier rather than a less expensive digital keyboard.
An adjustable piano chair or bench - kids arms and hands should be at the same height as an adult. Not reaching up from below or too high from above.
A footstool - this provides stability for kids who can't yet reach the floor. Without this, feet are dangling, backs are getting sore and balance is off. Adjustable is best.
The best possible sound sources for listening to music - consider a good quality speaker system that can play CDs or that you can connect to your media source. A high quality headphone system is also an excellent way to listen without distraction.