You could ask at your GP surgery (don't be embarrassed, they've heard it all before and won't even think twice - but don't book an appointment for it, just ask at reception) or a pharmacy. I think some places still do 'C-cards' that you can get at a sexual health clinic that let you pick up free condoms at Boots and other places. Also, there are usually sexual health clinics around university areas, so you could go there - you most likely wouldn't need an appointment, just ask at reception. But as MrsSheldonCooper said, loads of condoms get handed out at fresher's events, so utilise that too!