Yes – fee structure varies by the type of bond we are talking about.
Bid Bond : Typically a flat fee, sometimes they are free
Performance Bond : A percentage fee of the contract value, depending on the total value of contract (think 1-2% for a $1M contract).
Payment Bond : A percentage fee of the contract value, since they are usually always required if a payment bond is required, the fee is usually presented as a single number for both.