It’s NOT possible to know if your eligible prior to redeeming.
The pop-up offering the deal appears after the Apple gift-card has been redeemed into your Apple Account.
There is no requirement to spend / use the redeemed amount; it just sits in your Apple Account until you utilise it.
Gift-card redemption amounts $5+ have worked (ref comments below re $5, myself and another user did $50).
Can cancel Apple TV without losing balance of Free period (cancellation pop-up confirms that).
Where did you get the $5 gift card?
AIA vitality weekly challenge
Sometimes I get a few months of Apple Fitness +, I think the offer varies
Thanks OP! Added $5 GC and offered 2 months :)
Anyone had any luck with existing accounts or nada
I've had an Apple Account for many years (think that's not probably relevant)
I've not had Apple TV sub for >6 months (no sub for Apple One or Music))
Recently bought the Gift-card through insurance rewards (discounted).
If enough people add in their factors, we'll be able to build a what-works / doesn't - I'll update OP then too.
Mine was existing account with many past free trials.
Didn’t work for me, I only just finished a 3 month free trial, that is probably why.
Worked for me off a $30 gift card. My sub had been expired for several months. Was a nice surprise.
Didn't work for me, likely as I had finished the 1 month free offer (https://www.ozbargain.com.au/node/956037) the day before.
So I signed up for another month using the gift card balance I had just added. I then immediately cancelled, and was offered a promotion of $7.99 p.m for 2 months.
It was $5 gift card for me that triggered the offer.