ohh I've got one of those blackjacks Jane (half pint size)
They are really very nice but be careful not to squeeze them and crack the proofing interior.

If you look in your local charity shops you can always find some good quality pewter tankards at very low prices but cider is a no no becuase of it's acidic qualities.

My favourite 'tankard' is in fact an early Victorian half pint measure (complete with standard mark) but it is very heavy in lead content.

Good luck and slainté.