The alternative cost for both Force of Will and Daze would be reduced by 1 colorless mana to 0 (something cannot cost less than 0). Then Trinisphere 's effect would apply to both of their costs and the would each cost 3 colorless mana.
TL;DR: Trinisphere always wins.
May 24, 2014 8:51 p.m.
Lodestone Golem will still add (1) to a "free" spell like Force of Will . The alternate cost becomes the starting point to determine the cost of the spell, then you apply any modifiers in this order: Add, Subtract, Set.
So if Trinisphere was out while a player tried to alt-cast Daze , the starting cost would be "return an island you control to its owner's hand". Then we'd apply Trinisphere and the cost would be "return an island you control to its owner's hand" and (3).
May 24, 2014 8:52 p.m.
Oops, I misread Lodestone Golem . GreatSword is correct. The cost changing effect is applied before you apply the Trinisphere effect. When you have Trinisphere out every spell you cast will cost at least 3 mana to cast.