I suggest, like Christa that you set a limit. You can then budget around that. So, say you what to spend $15K, well then you will have to guestimate on certain things but as you spend, if you go over your projected budget in one area, lessen the budget for another.
How many people are you inviting? I don't think $1000 is all that bad. I know a lot of us are making our invitations ourselves... thanks to clever ideas from people who really know how to make them Could that be an option with the design that you love? Maybe you should post it and we can help you decide!!!