Alterations cost

I know this varies widely by a million factors (location, dress structure, etc) but I’m hoping to get a ballpark figure of what I should be budgeting for alterations. Right now I have $300 and I’m wondering if that’s realistic and what I should expect when I start looking for a tailor in a few months.

I’m going to need the gown taken in, the straps shortened, a hem, and a bustle for an average-size train. Would love to hear what others paid along with the work they had done and the location.