I need help with choosing my next musical instrument. I used to play the diatonic harmonica, but I plateaued after learning all the basics. Another reason why I stopped liking the instrument is that it's not suitable to play classical music, which is something I'm interested in. I really like the viola/violin, but as I've found out it's probably too hard to learn by mostly self-teaching (let's say one lecture a fortnight). I'm not sure how woodwind instruments, such as the clarinet compare. That said I'm quite open to all options, but I'd like to stay at reasonable budget - I consider instruments like cellos and saxophones to be too expensive.
Any feedback will be appreciated.