Commerce discounts by day-of-week and by age
You can use rules for first requirement. You will need to add PRODUCT PRICING rule &amp; check the day in condition. Just multiply the base price by .5 &amp; you can apply what you wanted..
Anther things are user role based, so if a user has role of student in condition then do the same in another PRODUCT PRICING rule.

Add one more rule for senior citizen, check their user type &amp; apply the new price.

These will work for sure..