Dealership finance refers to car dealers that offer car finance for their own customers. Although this can be a convenient way to finance your car purchase, you are limited to the finance that the dealer is offering and dealers may add commission or fees to the total cost.
Sourcing your own car finance independently, from a direct lender or broker, will offer you more choice and could result in a cheaper deal. You are also more likely to find a more flexible car finance option that better meets your requirements, as well as having the freedom to buy any car from any vendor, not just from a specific dealer.