Rent...you will have more fun. Just pay your mortgage off when you're older and earning lots, spend your youth spending what little money you have on enjoying yourself.
Saving a £100 a month isn't that hard either...do that for a few years and then just before you decide to finally get a mortgage make a real push for a few months to save more and it is easily done. I don't do this by the way, I blow all my money.