Most formal dresses need only a hem and maybe a little taking-in on the bodice. Hems start at $35 usually and can go up to $70 if there is an overlay and a lining. Taking in the bodice is ranges from $35 to $60 depending on where and how this needs to be done. If you have the problem of the dress being too small due to pregnancy or other factors, letting seams out can cost more than taking them in. Sometimes a formal dress can be just as expensive as the wedding gown to alter. Usually they are simpler, but the cost can still be a concern. Alterations are always an unwanted added expense and should be avoided as much as possible.