Like choosing your character's Race, choosing their Culture also has certain advantages that come with being a native. Any advantages listed for SubCultures are only for characters from those particular SubCultures. Other characters may buy into the same Guilds or Martial Schools, or may purchase the same advantages, however they must do so at full price. Any native of the main culture may take the Cultural Advantages, however, choosing a SubCulture gives you an alternative choice. If you are playing a member of a SubCulture, you must choose to take either the SubCultural Advantages or the main Cultural Advantages, you may not mix and match or take both sets of Advantages. You need not purchase these advantages at Character Creation, they may be purchased later with EXP if you wish.
Please also be aware, you may choose a discounted buy-in to one Guild listed for your culture, not to both. Since all Guild buy-in costs are the same, the Reduced cost discount will automatically apply to whichever Guild membership you purchase first of those on the appropriate list. The Guild Halls keep track of their members' activities, including your memberships in other rival Guilds. They merely give you a break on your membership "fees" the first time, in order to entice you into joining them. Once they have their hooks in you, it is much more difficult to sway their generosity beyond regular membership perks. Each nation houses two Guild Halls, which are available to their citizens at a discounted cost. The Guilds support their nations as much as the nations support them, so it is beneficial for all to encourage citizens to stay local rather than travel abroad to join a rival Guild.