I was fortunate enough to have made FBS (D1-A) before the, essentially, requirement of spending years attending clinics became the advancement culture. Even then, working HS, NAIA, DII, and D1-AA was not a profit-making proposition, when you take into account the number of hours spent in legitimate rule study, video review, scrimmages, plus the cost of uniforms, equipment, travel, meals, etc. D1-A was profitable, but it wasn't a living. That wasn't because it was just a fall activity - it wouldn't have been all that great even if it were year round (and it still isn't). But, it is a decent supplemental income, even after expenses. Yes, the NFL can be a good living wage - and is, for a number of those guys.
Regardless if you aspire to FBS (or NFL), or are happy working HS and/or smaller college, those that truly want to do the best job possible simply have to put in the time and effort. Period. And that means a lot of study time and personal preparation, at a minimum. I can't speak for other states, but something around $100 per game for Texas HS football is hardly a profitable venture, for such dedicated folks. Similarly, working smaller college football has higher per-game fees, but there are also even greater between-game time & effort requirements. Still not truly profitable for those putting in the requisite time and effort.
Sadly, there are folks that care little-to-nothing about doing a first-rate job, and are only in it for the money. Those folks may be able to show a profit, because they have little-to-no expense, either financially, or in effort. Thankfully, they don't last long at anything other than HS football. We'd love to get rid of them at the HS level, too, if it wasn't for the pure "numbers" needed for HS football. But, they tend to languish in the lower levels (and complain about it).
The only thing you can do pre-FBS (or NFL) are things that will mitigate your losses. Sharing expenses for transportation, lodging, printing hard-copy study aids, etc., where permitted, can help. You may be able to take advantage of relatives, friends, friendly business associates, etc., for some of those same expenses. Like any entrepreneur, be as creative as you legally and ethically can in reducing "costs," since you have little-to-no control over the fees part of the equation.
Heck, even FBS guys (and gals) will take advantage of legal and ethical cost-cutting opportunities. Example: If you have a fellow staff official in a city with an institution you'll be working, and he is off that weekend, get him to chauffer y'all around, saving the cost of a rental car. Buy him a meal and a beer. Way less expensive than a rental car. You'll reciprocate for him some day, somehow. That creativity can translate to smaller college and HS officials, too. Be creative. Think outside the box.
But, trying to make sub-FBS football a significantly profitable activity probably ain't gonna happen. Just cut your losses as best you can. You can't do much about it, so just learn to live with the financial reality, and focus on the activity itself. Make it fun. Accept the challenge of doing it well and right, and let the fact that you are giving your best be the reward for a job well done. Put in the time and effort. If it is meant to be for you, you will get there (wherever that may be).
Robert