A Bump Up is a one-time feature that moves your ad from its position in the listings to the top of ads on the first page, just under any Top Ads. Your ad will stay at the top of the listings on the first page until other ads are posted and then your ad will start to move back down.
Ads on the first page of a category get more visits and more replies than ads on other pages. Giving your ad a Bump Up is a quick and inexpensive way to bring you more traffic.
If you want your ad to appear at the top of the page for more time you can purchase a Top Ad feature.
NOTE: In the Events category ads are listed according to event date and not time/date of posting like the other categories. So if you buy a "Bump Up" feature in the Events category this feature will only act as a "repost" feature, meaning if you purchase a "Bump Up" in Events categories it prolongs the life of the ad and resets it to expire in 45 days but still shows the ad in its relevant place in the category pages according to its event date.