concerning what keyboard to buy, I personally always recommend at least PSR550 as starter, if you can PSR1000. Now this is assuming that you are hoping to get to acceptable professional level of musicship one of these days.

PSR350 is good, but for serious music, you need eventually to get something better.

If you want to play music seriously, here is what I recommend:

1) learn the basics of music theory by either teaching yourself or taking some lessons

2) Avoid the temptation of "transpose" button

3) When practicing, avoid Auto-accompaniment.

4) Practice scales, chords and appregos...

5) Listen to perfomances by professional people in this forum and ask them afterwards about chords and technics...

6) for added bonus, talk to scottyee about some special chords...