Simplify the following text for a Grade 14 native English-speaking person.
Original: They can occur anywhere in the distribution channel , modifying either the manufacturer 's list price ( determined by the manufacturer and often printed on the package ) , the retail price ( set by the retailer and often attached to the product with a sticker ) , or the list price ( which is quoted to a potential buyer , usually in written form ) .
Simplified: They can mean a modification either of the manufacturer 's list price , the retail price ( set by the retailer and often attached to the product with a sticker ) , or the list price ( which is quoted to a potential buyer , usually in written form ) .