Best Practice
Add at least three suggested donation amounts (e.g., $100, $50, $35). The psychology for this is that most people won't choose the lowest value.
Providing suggested donation amounts can help guide supporters and encourage larger donations. Donations suggestions may include a ticket to the event for someone who might not otherwise be able to attend, covering the cost of a particular program, or different giving levels that demonstrate different levels of impact - for example, $35 buys 500lbs of fresh fruit and vegetables; $50 buys 700lbs of bread, cereal, rice, and pasta; $100 buys 1400lbs of milk, yogurt, and cheese.