Q: What should I buy as a beginner?
A: This, of course, depends entirely on what you want to do. If you have a reasonable knowledge of music and you want to play Jazz or classical music, a chromatic harmonica is probably best. If you want to play blues or folk music or the likes, a diatonic is best.
For blues you would not want to have a tremolo or octave tuned harmonica, because you can't get the juicy bends you need for blues on these.
Chord- and bass harmonicas are more specialized. Quality, medium priced harmonicas are the Hohner Chromonica (Chromatic), Hohner Marine Band and Special 20 and Tombo Lee Oskar (diatonic) -- BB