Yes, it generally must be used in some sort of trade. But that could be something as simple as putting it on t-shirts or other merch, sold via an online site like Cafepress.
If it doesn’t fit on a t-shirt, I guess you’re out of luck.
For everything you’d ever want to know about Trademarks, it’s best to go right to the source:
Rules in other countries may be slightly different, but that will give you the basics.