When I started my lawn care business, I was fortunate to have a friend with a 7x5 cage trailer who donated it to me. I attached it to the back of my family sedan and went to work.
As I would drive around I would see guys with their purpose built lawn mowing trailers, and their trucks or utes and feel a sense of jealousy or inferiority. I hoped one day to earn enough money to get the nicer equipment.
As time went on, I would bump into different contractors and learn about their businesses. People are only too keen to share advice or lend a word of warning. Everyone had a different opinion, so I had to weigh things carefully.
What I discovered, was that most of the guys that had the purpose built mowing trailers were unable to do much of the gardening work I could do with my versatile cage trailer, and they generally had to either fork up a ton of cash or go into debt to get the great big set up.
Upon further inquisition by myself, I discovered that most of them were charging prices from the 1980's and earning a lot less than I expected.
I carried on with my simple set up, eventually buying a ute for $1500, and another trailer for $1600 (another cage one) when I had the money in the bank to do it. I was now thankful that I wasn't in debt every time I saw a flash ute and trailer go past me on the road.
I didn't find that the extra expense to get the flash trailer would have paid for itself. Thus, I recommend anyone starting out to get what you can afford. As long as you can get a mower in it, you'll be fine.