Buy the one from academy. I have a 2016 15ft Jon with a 20hp. The guy I bought it from got the trailer from Harbor Freight and modified it for a boat. Because of the weight distribution, the tongue started bending. I took it to a trailer repair and had them replace the tongue with heavier square tubing. All that to say, I watched craigslist for months waiting for a decent cheap trailer, but never saw one. Like you said, the used ones were more than the one from academy.
Go ahead and get the one from academy, and start getting ready for the spring fishin’.