How to set different price by days ( fixed duration)

You can achieve that with 2 differents method, choose your preference! 

You go for single 

enter the fixed days you want :

Now you just have to use discounts based on the amount you want for each duration!

let's say you want these prices :

4 days = 300$

8 days = 600$

12 days = 800$

You just have to set your product price (on Shopify product edit side) to your first price (here 300$)

Then you have to do some basic maths with discounts :-)

By default izyrent app do product price x number of days picked = total price

4 days = 300$ x 3 = 1200$

8 days = 300$ x 8 = 2400$

12 days = 300$ x 12 = 3600$

So you just have to apply a discount amount on total price for each duration day! 

4 days = 300$ x 3 = 1200$ - 900$ = 300$

8 days = 300$ x 8 = 2400$ - 1800$ = 600$

12 days = 300$ x 12 = 3600$ - 2800$ = 800$