FYI
You can combine ebates + unidays discounts.
Here is what I did via my desktop using chrome
1) login to myunidays account
2) search/activate Samsung discount (unidays will redirect you to Samsung.com)
3) log in to Samsung.com account (you should see the unidays price if you go to the preorder page, but you don’t have to do so at this time)
Do not close any browsers/tabs
4) open a new tab on your existing browser and go to ebates and login to ebates.
5) search/follow the Samsung discount on ebates (ebates will redirect you to Samsung.com. “Noticed you still logged in to unidays and samsung”). Now you can follow the preorder page on Samsung.com and select your new toy and trade-in (if any).
I got over $40 discount on unidays and $65.97 cb on ebates. I selected the unlocked s9+ and trade in my S7.
So, discounts+trade in value/credit came out to a little over $400 in saving for me.
Happy shopping and enjoy your new toy.