You can add iCart upsell app to your store. It will definitely help you to achieve all the requirements you've listed in your question. It has many upsell options as follows:
All these options are available at $4.99 when your 14 days free trial gets over. Hope you will give it a try! Thanks!
I would recommend using Ultimate Special Offers with all features match exactly to what you're asking, all in 1 app with:
- In cart upsell (check Bundle or Upsell option)
- Add Free Gift, motivate customers to spend more by offering free gifts on orders above given order thresholds. You can choose to offer one or multiple gifts.
- Volume discount: offer a discount for volume tier, buy more get more discount
But if you consider using a separate app for In-cart upsell then check out these two apps:
Hope you find this helpful.