Portable Keyboards at Mega Music mean that it is an all-in-one, portable, light and affordable keyboard, with a built-in speaker system. They are a great place to start to play the piano.
Digital Pianos are the more expensive cousin, that look and feel like a real piano, often with stands or cabinets. We sell those.
Stage Pianos are for the serious live or studio musician, and plug in to PA systems with sophisticated features. We sell those, too.
Synthesizers are used to create new sounds, popular in dance and electronic music. We sell those as well.
Pianos are the real thing that weigh a tonne and might be found at concert halls. We don't sell those.