First, we need to identify the verbs in the sentence:
"It will cost a lot of money to remodel that building"
The verb we need to modify -change to simple future negative is "cost", because the other verb (remodel) in that particular sentence is used to explain what action (to remodel) will be expensive, you need it in infinitive (just as it is now).
Then, we change to the negative form, simple future:
"It will not cost a lot of money to remodel that building"
or, we can use the contraction "won't":
"It won't cost a lot of money to remodel that building".