Experts warn that many people are spending too much on kids’ birthday gifts. The experts say for your own kid’s birthday, $100 is good. That’s enough for a great blend of toys, books, and clothing. They also say when budgeting, don’t forget to factor in the cost of a birthday party which on average costs about $400. As for other kids’ birthdays, they say $20-30 range is good… no matter the relationship.