Now my actual first bill come and I am a bit of shock.
When I first subscribed in early April 2020, paid $30 upfront but it is not considered as first bill. So my 1st May 2020 bill came today and considered 1st bill. No $20 credit
1st Month: 1st April - $30
2nd Month: 1st May (1st Bill) - $30
3rd Month: 1st June (2nd Bill) - $10
4th: 1st July -$10
5th: 1st Aug - $10
6th: 1st Sep - $10
7th: 1st Oct - $10
8th: 1st Nov - $10
As you can see, best to sign up towards end of the month before the new month as it is pro rated.
$120 for 8 months is $15 on average.