Vault 101 is a convenient little Mac app that lets you create and share encrypted files and is currently and steeply discounted by way of $2 Tuesday from its usual $9.99 price to $1.99. The app lets you select files and folders to be password-protected behind AES-256 encryption (256-bit Advanced Encryption Standard).
To use Vault 101, file out its form to create an encrypted volume. Give it a name and password and select the source folder for the files you want to encrypt. Next, click the Create Vault button and choose a location for your encrypted volume.
You can also opt to upload this volume to Vault 101's servers, where it will remain encrypted for 48 hours. You will receive a link that you can then email to a friend or colleague, who will also need to receive your password to access its contents.