It is random who gets sent bonuses. But everyone gets the monthly bonuses - there are 4 levels. Level 1 is .50, level 2 is 1.00, level 3 is usually 1, and level 4 is 2.00. You usually have to buy like 40 offers for each level. But the midweek usually comes out on Mondays around 10 am and the weekend usually comes out on Thursday’s around 10 am if there is gonna be one that week. It is usually a lot better $ for fewer offers. If you follow the midweek and weekend bonuses, you will make the level bonuses.
I usually finish level 4 in week 3 of the month, but I shop a lot to donate to food pantries and others in need.