Commit, commit with stipulations, or don’t commit at all. ‘Maybe’ leads people on and only procrastinates the real answer. ‘Maybe’ hardly answers the question and forces you into an awkward corner where you ultimately have to decide. ‘Maybe’ usually means ‘no’ anyway, so why not be honest?
You will disappoint people more by leading them on and saying ‘no’ later than if you just say ‘no’ now. And who knows? Say ‘no’ now and they might return with a better deal.
Decide. Stop wasting people’s time. Stop wasting your own time. Yes or no?