Do you want to exclusively express, or just now and then? If it is only now and then, a cheap manual pump might be sufficient. But if you want to do it a few times a day, go for a decent electric pump (like a medela freestyle). I have two medela mini electric, and both have their problems and really aren't suited for the exclusive expresser but could be ok for once or twice a day.

I use glad snap lock bags to freeze EBM, laying flat, and it is space efficient and BPA free. No need for expensive EBM storage that way .