“We might as well stock up.”
You're shopping at a grocery store with your son. You see that toilet paper is on sale there, so you think it's a good idea to buy a lot of it now. You make this suggestion.
We might as well stock up.
Saying that you "might as well" do something means that:
- you think it's a good idea to do it
- it's easy to do
For example, buying a lot of something while it's on sale is a good idea because it's cheaper. If the item on sale is also easy to carry and to store, then there's no reason not to buy a lot of it:
We might as well buy a few more.
Another example of "I might as well" is:
To "stock up" means to buy a lot of something, so that you'll have it ready.
Use "on" to express what you're buying a lot of:
Make sure to stock up on food and water before the storm hits.
Cigarettes are cheap over here, so a lot of people who visit stock up on them.
People usually stock up on consumable goods, like food, drinks, batteries, paper towels, etc.