Hi, I am looking for an used digital piano for my kid. She is 8 years old and has been taking the piano lessons for 1 year. There are two digital pianos available, CVP-305 (2 1/2 years old and no warranty) US$2,150 and CVP-401 (1 1/2 years old with 6-mth warranty) US$1,850 or Brand new CVP-501 US$2,500 with 1 year warranty. Pls advise!!! Thanks!