(MadridMan's translation to English below...)
I'd like to know where I can buy a pair of Real Madrid tickets. I'm thinking to go next year and I'd like to see them play. Can you buy them at the stadium or to do you have to buy them in advance?
Thanks.

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Me gustaria saber donde puedo comprar boletos pare ver al Real Madrid, Pienso ir el proximo año y me gustaria verlos jugar, los puede uno comprar en el estadio? O los tiene que comprar uno por antisipado?
Gracias.

You can buy them in advance and i suggest you look at their website which is here this link is for the english version which may be of some help.