alterations cost as much as the dress?

hello everybody ,
my friends told me that the  alterations  cost as   much as  her wedding dress,  it  was 300 total (and her wedding dress only 30 dollors more than that), oh! it is too expensive, and if  my wedding dress needs some alteration(i haven't choose my wedding dress yet), how can i   save my money?  altering a wedding dress is a tremendous amount of work! oh , god DANG!