3 types of products in invoice

[Joshua Willing Halpern]

Hey, I want to create invoices with three different types of line items, 1) rental items, 2) people for hire, and 3) rental add-ons.

 

Should I place all three in a single products table with extra child tables for each's type-specific info or should I create three different foreign keys in the line items table and create relationships to all three tables?