We offer online payment. We have smart phone with readers. That works great for us at shows, even in the nursery, or with me while out estimating, sold the job, say we want a deposit, they wip out credit card and scan it right there. I also offer intuit payment on every bill that is sent out. We have a 5% retention rate on payment with that method. I use some business checks but it amazes me that we receive so many checks in the mail yet, let alone using the mail, envelope, stamp, etc. I send all bills out via the mail, some prefer email bills as quick books offer that as well.
Landscape jobs, retail items are marked up much more than the 15% someone mentioned above. All landscape jobs are required a deposit.