in general, there is almost always an sql solution which makes looping unnecessary, and this is true in this case as well
Code:
insert
into Item_Billing_Link
( Product_ID
)
select Products.Product_ID
from Customers
inner
join Products
on Customers.Cust_ID = Products.Cust_ID
where Customers.Bill_Cycle_ID = '1'
and Products.Recurring = 'yes'