In Ireland, the average traditional Irish wedding is 25k – 30k. I am getting married next year and the venue alone is 15k. Photographer, 3k, videographer 1.5k, wedding band 3k, dress 3k, flowers I'm not sure but a couple grand likely, invitations could be 1k. Those are the larger costs and then you have smaller ones which add up.
The wedding industry definitely takes advantage to increase their costs. For example, if the band is hired for a bar on a Saturday night it might be 350 euro. But a wedding is 3k. Same for the photographers and videographers.
You would usually get the money back as you'd be inviting between 100 – 200 people and they'll give you money in a card. If you are lucky to have parents pay for it, it's 100% profit. If not you'll probably make a small profit of a couple grand to put towards a honeymoon, house deposit, etc.