When you are negotiating prices with your customer, you might say "that's $200," "that'll be $200," or "that would be $200." Are there any differences among them?
That is $200 means the current price is $200. You could tell this to someone who has not expressed any interest in purchasing the item, or you could use it with someone who is actually buying it.
That will be $200 is only used when the person has bought or at least is getting ready to buy the item, and needs to know the price.
That would be $200 is somewhere between the other two - slightly implying that the person you're talking to might buy the item, but not nearly as decisive as will be.