Time to weigh in since my title as group cheapskate appears to be threatened here.
My big thing for saving cost would be to buy/obtain used GMAT prep software from someone else. Lord knows there's been plenty of people who've already taken it. And it won't be scribbled on like a book.
I got a Kaplan prep CD from a friend (who only paid something like $20 for it in the first place) which had a diagnostic test and 4 real ones, plus 5 or 6 problem sets for each type of question (reading comp, arithmetic, geometry etc). I also found a bunch of free tests online, one was at like
https://www.crack-gmat.com or something like that, and of course the 2 free official tests you get from mba.com.
So for me:
GMAT prep: $0
GMAT exam: $250
Additional Score Reports(3): $75
Official Transcripts(3): $15
RT Bus to MBA fair(duke/haas/wharton/ross/stern were all there): $40
Haas/Wharton/Columbia/Duke apps (fee waived due to being a PCV): $0
Kellogg app fee: $230
Sloan app fee: $230
Recommender gifts(2 $15 gift certs to Amazon): $30
Buses/taxis to meet up with Wharton/Columbia/Kellogg interviewers in my city: $10
Skype costs for my phone interview with Duke: $1.20
Total cost: $881.20 US (but considering my results so far, perhaps a campus visit could have really helped)
*disclaimer: With the current exchange rate that's more than my monthly salary here!