For those who haven't seen it, Blizzard has just reduced the price of WoW and the expansions;
info found here
http://us.battle.net/wow/en/blog/1220626
US Server Prices:
WoW $5US / $2.435 CLP / $20 ARS / $62 MXN
BC $5US / $2.435 CLP / $20 ARS / $62 MXN
WOTLK $10US $4.831 CLP / $40 ARS / $123 MXN
Promo page: US
http://us.battle.net/en/promotion/
EU Server Prices:
WoW €5 EURO/ £4 UK / 69 RUB
BC €5 EURO/ £4 UK / 69 RUB
WOTLK €10 EURO/ £ 4UK / 129 RUB
Promo page: EU
http://eu.battle.net/en/promotion/
Offer ends 30th Nov