I, you, etc. could use a drink, etc.

(one) could use (something)

One needs something; one would be or feel better if one had something. After the week I had, I could use a stiff drink. You could use a new suit—that one's looking pretty shabby.
See also: could, use

for one

Used after a name or personal pronoun to emphasize something about oneself or someone. The phrase is more formally set apart by commas on either side, but these are often omitted in everyday writing. I can tell you that I for one am really happy about the changes to the tax law they've introduced. A: "Who is coming to the movie later?" B: "Mary, for one, but I haven't heard back from anyone else."
See also: one

I, you, etc. could use a ˈdrink, etc.

(spoken) I, you, etc. need a drink, etc: We could use some extra help just at the moment.
See also: could, use