I know this has been posted around the same price over the last few months but still the cheapest at the moment:http://www.guildwars.com/products/factions/
No monthly feesever! (it says) :)
4 new distinct regions to explore
2 new professionsAssassin and Ritualistproviding 56 dual-class combinations
300 new skills to unlock and use
Over 200 quests
Alliance battleslarge-scale PvP battles that allow factions to redraw the borders of the Canthan empire
Again, i hope this is of use to someone..