Not properly translatable

Unfortunately, the current version is not properly translatable due to this code:
$other_notice_html = '<p class="sbi_other_notice">' . __( 'PS. We currently have a <a href="https://smashballoon.com/instagram-feed/?utm_campaign=instagram-free&utm_source=notices&utm_medium=rating&discount='.$sbi_bfcm_discount_code.'" target="_blank"><b style="font-weight: 700;">Black Friday deal</b></a> for 60% off the Pro version!', 'instagram-feed' ) . '</a></p>';

It stops being translatable when you start the concatenation with the $sbi_bfcm_discount_code. Please use sprintf for this.

Additionally, it would be great to not have HTML inside translatable strings. Please use sprintf for this, too. This would make it much more easy for us to translate your plugin.