We require a minimum of $10 for each donation because of the fee structure. Our payment processor charges a percentage on all donations, plus a $.30 fee on all donations.
If someone were to donate $2.00 to you, the fees would be $0.04 + $0.30 = $0.34. That's almost 15% of the total donation.
When someone donates $10.00, the fees come out to $.19 + $.30 = $.49. It's a much smaller chunk of the donation and will ultimately help you raise more money.
I hope that helps clarify. Please don't hesitate to reach out if you need any more assistance.