This really depends on your relationship with the family. If you are a friend or acquaintance, anything over $50 is recommended. If you are a close relative, $100 to $200 is acceptable. Godparents typically give more, anywhere from $200 to $600.
However, if you are struggling for money, the family will understand, and you can stick to your budget.
A general rule of thumb is to pay around one week’s salary for the gift. But this is more for close family members, such as aunts, uncles, or godparents.