On cutting the openings: it depends on the container, absolutely.

The opaque bins were cheap steralite. I drilled four holes with the largest bit I had. Then I used a jigsaw to cut out the hole.

The blue bin I used was rubbermaid. I stuck a regular knife (stupid, cheap steak knife) in and cut away. It was really easy.

I'd never do anything but rubbermaid again. It's worth a bit more money for the ease.