You will get more bang for the buck with a used trailer. The little Home Depot ones with the small wheels are fine for short hauls. But I often need to travel over 1000 miles for a river trip. Getting a trailer capable of safe travel at sustained highway speed is a must for me.
I figure the greatest wear and tear on my gear (boat, frame and trailer) is not the few days floating but the 2-3 days driving. Impact with gravel at 70 mph, loose straps beating themselves to death, rough gravel roads and a trailer with spring leaf suspension....
I have a 9x4 utility trailer. I built a hinged deck for the top. It used full size light truck wheels (good for highway speed, common size) Over the years I have made some upgrades. I installed LED lights and a full ground wire (not frame ground) and have never had an electrical problem since. At about 5000 miles I had to replace the bearings and axles on both sides, due to wear.
In hind site I wish I had spent a little more and got a trailer with a better bearings/suspension system. The wear and tear of long road trips is more than I expected.