My children get lots, but unlike what irregular suggests, they're not spoilt or bored because we do not overindulge the other 364 days of the year, and so they're actually rather grateful for the gifts that they receive.
My DDs tend to get:
Xmas stocking (to open in bed and entertain if they wake up stupidly early!) 5 small little things like a magazine to read, chocolate to gorge on etc...
Once we're awake, they have their sacks from Santa. This is usually about 25 presents each and includes luxury food items they're not normally allowed (like bubble gum), clothes, books, DVDs etc... This usually includes 3 gifts that they request. I choose the rest, but it includes a lot of things they need.
From us: 5 big presents. This may be a £30-40 new gym leotard, pandora charm etc. this year the girls want iPad minis. We said if they save up the first half, we'll pay the rest (£125), so they're busy doing chores earning pocket money, saving birthday money etc for that.
As for other people, my parents also give them a small sack (about 10 - 15 presents) but again, this includes a lot of things they use and need as well, like the microwave beanbag toys etc...
Then from other people the girls probably get another 15 - 20 presents. But these won't all be opened on Christmas Day.
For cost, haven't a clue but it's easily hundreds of pounds. But they only get about £50 on presents for birthdays (I buy a party instead) and I don't buy toys during the year - they want something they need to save pocket money for it. It also includes a lot of their clothes. Dds have asked for some nice / trendy clothes this year, which they'll get.
They'll get a lot, but our house won't be filled with tat on Boxing Day
.