You can find details of the theme on the
JobRoller theme page, including links to the front and back-end demo from there.
Theme documentation is also available to view if you wish to get an idea of what is involved with setup/configuration before you purchase.
With regards to your specific question, JobRoller allows you to add job listing plans which allows you to set prices for single or multiple job listings, for a set duration as you have described. You can see the settings for this on the
JobRoller admin dashboard demo here. Thanks.