I have no adult children yet, but we give around $200 to our kids for birthday & Xmas.
My parents are in the Netherlands and we give each other around 100 Euro for a birthday.
It’s about the gesture, I suppose it depends on that what you have to spend and that what you want to spend. But a handmade gift may not cost you a lot of money and has a higher value.

It was $200 each until my grandson came along, now it’s dropped to $150 each. My grandson doesn’t have a limit

I think $50.00 is reasonable.

Usually $50- $100, unless i laybuy early or pay something off in Chrisco

Not usually more than $100 sometimes $50. I think it depends more on the thought of the gift than the price

I think $100 is reasonable for adult kids.

I know my mum spends approx $50 on me for my birthday’s for xmas as a family we do a kris kringle & our limit is $50, if that adult is in a relationship which most of us are married we can combine the 2 adults together so they have 1 present for $100.

Just a card I think.

On Christmas it is $100 and birthday the same.

I always pay my sons ambulance cover on his bday and then just get him a few tops or something like that and about $250 at xmas

I don’t have adult children yet but my parents spend $50 on me.

I find it hard finding presents for boys. Girls are easy.

About $100 each adult?

It depends. For Christmas around $50 for my husband, $100 for my daughter, $20 for other people. For birthdays $50 for family members, $20-$25 for other people.

It depends on the circumstances. If we knew what was needed that was a bit expensive for one of us on our own, my Mum and I sometimes combined funds so there was enough money to pay for it. Everybody understood the present was from both of us. It was far better to buy something that was needed and would be used. e.g. one year my Mum and I bought my brother a good quality electric drill kit that he coud use at home or at work. We knew that his other one had just “died” and would cost more to repair (if parts were available and we had doubts about that as it was old and the original manufacturer had closed). The best option was a reliable good quality new one.