Does your band have merch? Yes? Great! No? Why the fuck not?
Before you are playing shows, you should have merch. Merch serves a multitude of purposes. For one, it is additional income for your band. You will need and want additional income. Second, it is a great gage of how much fans enjoy your music. No one is buying your band shirt if you suck. Now, granted, someone may buy it if they haven’t heard you before and your design is top notch, but the reality is going to be that it is going to be much more of your fans and people who know your music that want your gear.
Unless you’re SLAYER and then even people who don’t like your music will buy it (looking at you, Kylie Jenner, Justin Beiber, etc).
Your merch needs to stand out but it also needs to be in line with your style of music. Rap merch and post-hardcore merch should look pretty different. Each one of your favorite musicians have merch for sale online. Go look at what they are selling. It is going to be shirts, hats, and probably a bandana (if rock/metal), and then some.
So keeping those three items in mind, let’s review what else you can sell –
Boy shorts (no one does this and it amazes me – someone, somewhere, please start doing this)
Some things you should just give away. Guitar pics, stickers, pens, all should be very cheap to buy in bulk. Take the financial hit on them and show your fans/a crowd you care.
As for what the design is, keep in mind that it does NOT have to be just your logo. You SHOULD have your logo on some of your designs, but just put some edgy lyrics on the back of a shirt and throwing in a color or two. Keep it simple but make sure it looks good.
That means going to a quality graphic designer to make it for you.
Pro tip – If they don’t charge you, find someone who will. No one who is good at something does it for free.