Clicking can come from all sorts of things on a bike...I'd let a shop take a look, or spend some time online (even here) with more specific info. to get a sound diagnosis...THEN go learn how to fix it.
It seems a lot of people run into a problem with an old bike (or just look at it and say 'that is old') and want to look at replacing it, while not spending much money (and so typically cheaper used bikes)...this is pretty fascinating, as it is often a lateral move, and can cost more than just fixing what you have, while missing the opportunity to learn about bikes and repair (saving more money).
I don't know if a different bike would be better for the OP, but I wouldn't jump ship because of clicking on a heavy bike. If you want a different bike, great, but I'd learn a bit, fix what you have, and then see what you think...if it is fixed, then you can at least sell it with confidence.