Battle: Attach a target Weapon from your hand to Hongo
My question is do you still pay for the weapon's gold cost ?
Hongo's ability
A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
My question is do you still pay for the weapon's gold cost ?
Yes.
Unless its cost is explicitly ignored as an effect, whenever bringing a card into play, you must pay its cost.