Ways to keep Mosquitoes and Bugs out of the Cave if I dont put up a screen

I have an 18x21 mancave with an 8x7 garage door and a 24x80 walk in door. I anticipated keeping the car in it until I got my other garage up which is why I put the 8x7 on it. If I hadnt already put it on, I would have been able to easily do a nice screen setup with screen door or something. Well now, I just want to be able to keep out the bugs and mosquitoes. I have looked online at the garage door screens and checked the reviews and stuff and it seems like alot of people had to make them work. Somehow it was something that didnt fit properly or something, didnt come with all the magnets or velcro or something, and also the customer service was bad. Also read a lot say upon ordering, they were billed for multiple items and had a time getting their money back and some never got their money back.

Yeah they are about 20 bucks but still I may not want to go that route. If there is some kind of inscent or something that I can burn in the cave, something that's not bad for humans, or something please let me know or give me some ideas on something else. I can hang a curtain up at the walk in door and for the 8x7 with the door up I was trying to see if there was maybe a curtain or something of some sort that I could put up, take up and down when needed or didnt need. I would want it to be able to flow air possibly, though there is a window and vent also above the door. Air would be able to escape pretty well as there are some draft areas on the cave also. I bought a 24 inch Max Air fan from home depot so that should circulate very well in there. Just trying to see how I can go about keeping out most of the flies and mosquitoes. Having those doors with something in front of them would keep a billion from just coming right in. I probably can still burn some kind of thing in there that will shy them away some????????

Thoughts?????????