While she'd just started seeing someone new, it was very early days - far too early to discuss living together. Her friend since school, Sarah, was single and renting a room in a shared house in Brighton. The cost of rent or a mortgage, household bills and subscriptions can't be shared. And a single person pays 25% less council tax than a couple - not half. Many discounts involve pairing up - 2-for-1 cinema tickets, Two-Together railcards, couples gym memberships - plus solo travellers often pay a single person supplement.