Snapchat has announced that it is capping free Memories storage at 5GB. If you exceed that limit, you must export your data or sign up for a plan. The introductory price starts at US$1.99 per month (around CA$2.78) for up to 100GB of storage. If you don't want to pay, here is how you can download your Memories.
You can cherry-pick the Memories you want to keep and download them 100 posts at a time. Open the app, then select the Memories icon next to the camera button. Tap Select in the top right corner and choose the posts you want to keep. Then, tap the Export button that appears at the bottom right of your screen and select Download to save them to your camera roll. Rinse and repeat as needed.
If you find that option too tedious, you can choose to download all your Snapchat data. Head to your Profile in the app, then tap the Settings icon on the top right of the screen. Scroll down until you see the My Data option. You can choose the Memories option from there and uncheck the others. Tap on Next and pick the All Time option. Confirm the email address where the .zip file will be sent and tap on Submit. It could take some time to get your data, depending on how much you have stored, though.
Snapchat has given users 12 months of temporary storage for those who exceeded the cap. However, if you are over the limit and don't sign up for a plan, only your oldest Snaps will be retained, while the recent ones will get deleted, so you stay within the storage limit.