Oh yeah, of course. I forgot about advance tickets because there weren't any available to get me to Stansted for my flight (needed to arrive by 12pm).
Even now the cheapest tickets from Nottingham to Stansted are £52 sans railcard for the end of January. Maybe Nottingham-Stansted airport is a special case?
Some digging and there are advance tickets to Ely available for £5, and Ely to Stansted airport is £14 for a regular ticket.