FYI: Microsoft Rewards is now offering Xbox Game Pass. 1 Month or 12 Months.
As it stands at the moment I think it's possible to get free Xbox game pass out of these rewards.
You need to earn 6,800 points per month (you'll be level 2 and get a discount from 7k).
You can get 60 per day from mobile search, and 90 a day from PC search...which is only 4,500 per month BUT up until August there is a double points offer by searching via Edge.
I need to test again today but that lets you get another 180 points (it seems separate from the PC search quota) which comes out at 9,900 points per month.
If the PC and Edge searches don't stack then you can still get 60 from mobile and 180 from edge which equates to 7,200 which is more than enough.
All these figures ignore the little quizes they put up each day which seem to be 30 points each. I've only just started so I don't have a feel for how often they put them up, so I haven't included them in any calcs. Obviously one of these a day is another 900 points in a month.
FAKE EDIT - all this assumes you want to get game pass via the monthly method. I just checked and the annual purchase is WAY cheaper. The monthly method is 81k points for a year BUT the annual purchase is only 29k points. Based on this I am going to try and save up and buy the annual pass....will take 4 months to do it though!