Q: do i need 88 keys (i dont think i can play classical music on a 2 octave keyboard but it might be enough for other styles.
A: too octaves way too few, but 5 octaves may be just right. befriend the octave switcher button, should be right there on the front. but with 5 octaves you won't need to even use that button very much where as with a 2 octave keyboard let's face it you will be one a one handed player because the other hand will be on the octave button the whole time and good luck playing in B