Snowball this is my trade and how much depends on yardage in skirt of dress and what way the cloth is cut
If it's cut on a bias it will require a couple of lengthy fittings otherwise you have to look at how many layers there are
Presuming there's at least one plus a lining
I charge E20 to shorten an unlined simple skirt E30 for a lined and as for wedding dresses / Evening dresses (same type of fabric just diff colour) it ranges from E50 -E200
Last one I did had 7 layers I kid you not It took 3 fittings cost 150