I have 2 adult bios with spouses and 3 grandkids and 3 step kids.....$100/person.

My adult bio's between $50 and $100 each. I buy them "Dinner for 2 LivingSocial deals" that they can use for date nights with their significant others. Depending on the deal, they run between $50 to $85 for a full 3, sometimes 4 course meal, at really nice restaurants.
DH just spent $100.00 on SS21 (who he isn't even on speaking terms with) but I guess it's his way of telling him he still thinks of him, which I guess is ok.
On my youngest Bio, anywhere between $100 to $200.
On SD13, who knows. It's always a free for all on that one. Supposedly, this year, it will ONLY be $200.00 for a pair of Jordans. But we'll see, DH might sneak in more shit because God forbid she only opens ONE gift at our house.

No adult stepkids here but I know that my in-laws and parents get me and the other adult married "children" something for the couple usually a gift card to dinner and a "fee babysitting" coupon. Then we usually get something small as an individual (shirt or trinket of some kind). Probably less than $100 each. Our kids however have the ever loving crap load spent on them. My mom usually does about $700-800 kid and my MIL about $300. They are spoiled beyond belief! Grandma's do way better than Santa every year. It is rather sickening...

I had a big post about this a while back. It's was about Quality vs. Quantity. DH and I use to have a set amount for each kid. But as they got older their wish lists began to become more unique to each of them. This year we are not going to worry about a set amount for each child, but more on something that each will really love and use for a long time. SD13 got a laptop (which she is already banned from) that was about $200. The boys will get a second xbox and new controllers each, $180 and two $50. The amounts are not the same but the gifts are geared more to what the individual child wants.

This year we have budgeted the following:
My bios who are 11, 14 and 16 = $250 a piece
My 2 SS's who are both in their 30's = $100 a piece+ a card
Spoiled SD who has disowned us via a tantrum like a toddler = $0.00+ no card
My DH devised the budget and asked if I would agree. I thought he was being quite generous to my kids but they live with us and my DH is very close with them. They treat him with respect so I guess he feels like they deserve a lot this year. Their father never buys them a single thing and doesn't want them on Xmas day or Xmas eve. He's "too busy". I wonder if my DH is trying to compensate for the fact that their father ignores them every year. I don't know but $250 a kid is extremely generous. We are grateful.

Dh has 3 adult sons and I have 4 adult daughters (all in their 20's and early 30's). We're giving $100/a piece, although, if my DD26 doesn't give me the time of day this Christmas Eve or Christmas Day as she did last year (and the year before, she told me "coming to my house, WAS my gift"...whatever) she won't get squat. Little twit. The girl needs to grow up.

Actually dh and I had a big fight over how much to give this year as he is unemployed at the present time. He said $50, but I have NEVER given my DDs less than $100 plus we are far from distitute and I know my DDs will get twice what we give them from their father/stepmother. WE'RE the poor relatives.