"Can I freeze lemon juice? Or am I better off with bottled lemon juice?"
Freezing fresh lemon juice works quite well: I like to freeze mine in ice cube trays. I do not recommend bottled lemon juice, however; it has a somewhat chemical flavor that is quite different from fresh or frozen.
For some tips on juicing a fresh lemon (or any other type of citrus fruit), see our video How to Juice Citrus Fruit.
Recipe: Vanilla-Rosemary Lemonade