This is a very broad question and I will interpret it as getting online clients. The most inexpensive way is to create a quality website based on a previous research which identified the niche or lets say the most wanted flowers. The more pages, the better. I have many sites on different platforms, but the one that brought me the full understanding of the internet was SBI.
Please see my page: https://www.flower-arrangement-ideas.com/starting-an-internet-flower-business.html