Weddings, not sure if i said in previous post - we spent about $25000 on the wedding day itself, split between bride and grooms family 50/50. (including venue, food, flowers, video, photographer) This did not include alcohol, the venue let us bring our own, one of us (i think grooms father) bought a couple of cases of wine and some spirits. Most religious women don't drink a lot, some religious men do. I might drink a glass of wine at a wedding but hate any other alcohol. also tons of the guests at religious weddings are kids and therefore don't drink.
Lots of people spend lots more than this, some people spend much less. I went to a wedding recently in London that was really no frills and it was lovely. Synagogue hall, basic food, they had to move the tables aside at the end of the meal to dance. I don't know how much they spent though and it was pretty untypical.
We don't do stag/hen dos. The shabbat before the wedding the bride and groom will have very low key seperate parties - auf ruf for grrom and Shabbat Kallah for bride. seperate because bride and groom don't see each other the week before the wedding. (some people make a bigger deal of the grooms thing, we don't). I spent about $300 on fruit, cakes, etc and a relative hosted in her home, and a bunch of friends/family came over.
After the wedding there are Sheva Brachot, and those can be expensive. Usually family and friends host them and its just the bride groom and immediate family but sometimes people will make bigger ones. For example one of my relatives had a really big sheva brachot (catered, in a hall) in his hometown for family members and friends who couldn't make it overseas to his wedding.
Me and my siblings usually host a sheva brachot for each niece/nephew who gets married