Certainly! For a lease bike, accessories up to 15% of the recommended retail price can be leased. The gross/net benefit also applies here. However, this only applies to accessories that can be attached to the bike, such as a different saddle, bike bags, crate, or new pedals. Exceptions to this rule are a helmet and a chain lock. For other 'loose' accessories, such as a rain suit or bike computer, this benefit does not apply and therefore cannot be leased.
Once you leave the store with your new bike, the lease contract is activated, and no additional accessories can be added.
Sometimes bike shops offer free accessories with the purchase of a bike during special promotions. It is important to know that these free accessories are not insured, as they are not part of the lease agreement and become the direct property of the employee.