I have all the tools to replace headlight and taillight housing and bulbs for probably most vehicles including semis.
For my Saab's headlight bulb replacements, I have to remove my front bumper and then the headlight housing unit itself, just to replace turn signal and headlight bulb. I am fairly mechanically advanced.
It's not quite just $10, it's $10 more than a single bulb would cost you at your local parts store. If you lookup how much a headlight bulb is these days, it's about $20. My service will be $30 flat for bulb replacements in my area with a small mileage fee for out-of-towners.
The great part about Minnesota, is most of us hate the cold. I however do not. Many people get lazy and will Doordash or find other convenient ways to have things delivered. Not many people want to change bulbs in the cold or bring to a mechanic to be over-charged. What my population is looking for is a service exactly like I am providing.
Again, the pricing of $30 per service is perfectly sustainable for me and I have no issues replacing most parts in vehicles, lights are a walk in the park for me.
*Will correct typos later, at work ATM.
What I really care about, is moving the world forward. This is a service that the area I am in, is lacking. I don't need to make excessive profit, I just need sustainable profit and I am happy to provide this service as it's well within my skills.