The primary difference between a sales and marketing funnel is your relationship with a prospective customer and where it takes place. A marketing funnel is the process of converting a prospect into a customer. This is accomplished through the five stages listed above: Awareness. Interest. Desire. Conversion. Re-Engagement. A sales funnel works to guide the prospective customer from the marketing stage to conversion, which takes place from the moment a salesperson contacts the lead to they point of them becoming a loyal customer. This has a three-stage journey: Top of the Funnel. Middle of the Funnel. Bottom of the Funnel.