I made a "just for fun" project last year where you can order a shirt with two US states.
My facebook friends got a kick out of it and I get a few orders around the Holiday season since its a fun gift idea. To be honest I've only ever made $250 in profit from this project since you only make a few bucks from each shirt sold.
Worked on a few new things this year including adding single state shirts, and redesigning a few of the existing shirts. And you can now also order women's shirts, hoodies, and kids shirts in any color.
I use the Printful API for making the shirts, so when an order comes in I don't have to do anything! The website is a custom Laravel app with Stripe for checking out.
SEO has improved over the year, but it's pretty competitive to be listed for single state shirts, and there just isn't high volume of people looking for 2 state shirts. Live and learn I guess!
I have no idea why I keep working on this project as I dismissed it awhile ago as not really being hugely profitable. But every Christmas season a few random sales come in and its kinda fun to play around with different designs and see what shirts people order.
Would I recommend it as a solid business? No. Would I recommend it for playing around and having fun with new ideas. Sure!