The basic 5$ gig will give you a cover pic banner perfectly sized for facebook timelines and events. There are some available extras so be sure to check those out, especially if you want unlimited revisions not related to typos or corrections.
Special Note on ordering extras:
When ordering a matching image, it is one extra per additional image. So for example if you want a profile pic and timeline image to go with the cover, that would be the basic gig plus 2 extras for additional pics selection. Please order carefully, thanks!