There's currently no way to delete notifications; however, if you'd like to turn off the notifications on your phone, please try the following steps:
1. Tap the "Profile" icon in the bottom right of your screen
2. Tap "Settings" under the "Info" section towards the bottom of the page, followed by "Push notifications"
3. Toggle the weekly/specials offers alert to "off"
All notifications should stop after you turn this off.