As stated above, you don’t need to have the full funds to purchase a Surety Bond. Even if you do have the available funds in full, you don’t have be concerned about having a large amount of your funds frozen in an account.
A Surety Bond is generally easier to get when compared to a Letter of Credit. You don’t need to have an established relationship with a surety company, whereas this is necessary for a Letter of Credit. However, you may end up paying more in premium with a Surety Bond, since a Letter of Credit typically doesn’t cost more than 1% of the amount required by the contract.