I totally agree with Driver
For the symptoms you mentioned I personally would not get it fixed. If it were just the tray not opening I would say try cleaning the rails but because the function buttons also dont work I would GUESS you have a power supply or logic problem or both but that is just my OPINION.
I wouldn't hesitate to buy used but do your homework.Let me take that one step further - look for forums for any manufacturer you may consider and read their posts regarding reliability and sound quality.
For the symptoms you mentioned I personally would not get it fixed. If it were just the tray not opening I would say try cleaning the rails but because the function buttons also dont work I would GUESS you have a power supply or logic problem or both but that is just my OPINION.