There is the actual cost to get something done, but there's also the hidden cost like Sparkz talked about.
For example, the custom seals. USPCC will charge you X amount to get those done, but are you the designer? Is someone else doing that for you? What's the cost if you're the one designing it or sourcing it? That adds up. What is your time worth to you?
Same with upgrade in paper stock, it could cost you more for postage. I know it's only so much more weight, but that can add up for international shipping as well as you ending up with more stock since you have to print more, which you might have to find a place to store it when you get the decks or might even cost your more to freight it all to you.
Your best bet is to look at things clearly and look at potential hidden cost associated with each upgrade and what not to see how much you should raise to make it worthwhile for everyone (include and your potential backers).