I spent most of my summer 2015 turning wrenches repairing or building equipment to help my youngest son start a lawn mowing business. This is how we built a trailer for his riding mower to tow a push mower, gas can, weed eater etc.....
I bought none of the materials it's all recycled.
Angle iron which were from bed frames
Wheels from a junk bike
the tips of the front forks of two junk bikes
tube steel I got from a futon frame
farm fence I got free
OSB for the deck from a pallet
two handles from junk push mowers to make weed eater/ leaf blower rack
I welded everything but you could use nuts and bolts.
Step 1: Make the Frame
First determine the size you need. I believe I made this about 3 feet by 4 feet. I wanted about as wide as the riding mower and long enough to easily hold a push mower and gas cans.
I design in my head and often on the fly. First I used wheels from a junk two wheel dolly. They proved to be too small and the bearings lasted about 30 seconds. So I switched to bike wheels from a junk bike I had picked up to scrap.
The change in wheels also required more frame work to support the outside axle of the wheels.
I cut things to fit as I went and welded them in place. In order to mount the wheels I cut the tips off the front fork of two junk bikes and welded them to the angle iron. This way the wheels bolted on just like they would on a bike.
I wanted sides on this like a truck bed so I cut 4 uprights 1 foot long and top rails to match the base.
Step 2: Paneling and Add Ons
For the deck I cut a section of farm fence then put a piece of OSB on top of that.
I used more of the fence for side and front panels.
Now for bells and whistles
I used another chunk of fence as a divider about 1 foot from the front. This holds a gas can and a milk crate with oil, funnel, etc
My son added a weed eater and leaf blower so I welded the upper half of two push mower handles to the side frame using the engine kill lever as the rack to hold both.
Something we didn't get to yet is a tailgate/ramp on the back.
Step 3: Finish
All in all this was fun to do and as you can see in one pic my son got to learn some welding.
Sorry I don't have more pictures. I've been sidelined for 6 months after double knee injury.
I did not explain every little step as you may not have a welder so explaining how to weld would waste your time.
Measurements were for our needs your may differ. If you attempt this I'm sure you know how to use a tape measure.
Cuts, I used an angle grinder and cutting wheel. But a hacksaw, band saw, cut off saw all work fine. Use what you have.
Source your materials as you can. All of mine were salvaged found on curbs or through Craigslist/freecycle.
I hope this inspires folks to recycle materials that would hit the dump normally. If you have the time and wait one can find darn near anything cheap or free.