Lancaster University Student Union (LUSU) offer two types of student card. The one advertised everywhere is the Purple Card. It has the NUS logo on it and gets you discounts and free drinks in shops, restaurants, pubs and clubs around Lancaster.
However, if you just want to get your regular student discounts (concessionary prices) at the cinema or theatre, and aren’t going to benefit from the perks of the Purple Card, then you can get a Red Card which costs just £1, instead of £12.50 for the Purple. You only save £11.50 but I don’t think I’ve ever been in a situation where a Purple Card would have benefited me, so I might as well. The URL for the Red Card is http://card.lusu.co.uk/red. I’m listing it here because the link doesn’t appear anywhere else online. The website for ordering the Red and the Purple cards are almost identical but the price at the end will be different.
As far as I can tell, the additional NUS Extra card is available with either of these cards, so that doesn’t justify the extra cost of the Purple one. The NUS Extra card doubles as an ISIC international student card and will get you discounts on Amazon orders for instance.