My company is marking up way too much. I know it, but I can't change it

[StillMcfuu]

Kind of hard to judge why your company charges what they do without knowing the specifics behind the billing. If I had to venture a guess, your company may charge a flat rate of $100 for the doo-dad you are selling. You are upset because the $20 chunk of that price that accounts what you do really only translates to about $15 of work from you.
My assumption is that the cost is upfront and if your company has to eat you spending $25 to complete your step of the process because you encountered an issue, they can't upcharge the client. There is also career training, materials, logistics, and administration that goes into your part of the job that may be accounted for under that flat rate of $20 in the overall bill. Also important to realize that just because you are bring paid $5 an hour, the cost of your employment is likely double or triple that number. You get $5 an hour but they are paying $15 to keep you employed.

If they really aren't charging a competitive rate that leaves them open to losing business to competitors and outside consultants. Which you can potentially slot into, but I can tell you from friends who have started consulting side gigs that they largely make less because things like insurance (health, business, liability) is hugely expensive and without the weight of a major corporation collectively bargaining for better rates those costs become extremely high for people out on their own. They don't start to see more money until they carry/juggle a higher workload than they would at their old employment. Where you can only do 1 to 2 projects at a time because of how things are scheduled and regimented when you work for an employer, when you are your own boss you can take on 5 projects and essentially get paid 5x in the same amount of time that your old employer would keep you on 1 or 2 projects.