Besides a dehumidifier, how do I get musty smell out of basement?

Musty small is form dampness. A dehumidifier is the best way to go. Small containers of a desiccant which absorbs dampness can be found at a Home store. But this will not draw out the dampness like a dehumidifier. If there are windows and doors, open them up wide, multiple days n a row and see if that helps.

I am not sure why your basement is damp but that is the reason for the musty smell. Using the dehumidifier is the best way to get things as dry as you possibly can. And if you have any rugs and carpeting in your basement that have been wet they need to be removed or professionally cleaned and any other items that many have gotten wet--boxes, linens, furniture as well. Every thing needs to be as dry as you can make it. I have 2 dehumidifiers running in my basement in the summer and I have to empty them on a daily basis and I have no musty smell. When it's really humid outside they fill up fast. I used to just have one but I found two is better. I have wood heat in the winter that drys out the basement well but the rest of the time I run the dehumidifiers.

We use a product called "VitalOxide" in our camper, get it on Amazon

If you do invest in a dehumidifier, make sure that you spend enough to get one that 1/ either automatically shuts on when the reservoir reaches max capacity or better yet, 2/ one that you can screw in a piece of garden hose to and then put the hose into your basement drain. With the second feature, it can be running continuously, and you will never have to worry about it overflowing.

You my need to dig up next to outside wall and get you some of that stuff that dude sells on tv and seal the wall in side and out.

I think that nothing will help you. I'm speaking from my own experience. In my garage always was a musty smell. I have tried to use different solutions, I left the door opened but nothing helped. Only the dehumidifier. I found a Dehumidifier Critic and read there about everything that I need in order to buy the best dehumidifier. You know, it is important to know the power and what exactly you want from it. The difference between them and all from this stuff. So I bought one and keep it one and clean it on time and the air from my garage changed a lot. But this is just my experience.

Humidifier will pull the excess moisture out of the air and follow up with charcoal and/or a bowl of vinegar.