I was in my local poundland shop in Norwich today and noticed that they still have a range of sun creams on offer for just £1.
They were spf 8 and 15 which should be good enough for most people. I tried the spf 15 last year in Spain and it worked fine.
Generally I have noticed that sun creams I have seen are much more than £1 and closer to the £5 for 200 ml. This might save you a few quid when you go on your foreign hols this year.