How much should I charge for 20 truck trailor lettering/decals for each of them 75 squre ft dealingr

[Derekaztec]

I should also add most of my work is not on signs for trucks or cars but decals stickers and labels, which allows me to stay in one place and
do multiple jobs at once. As i am new to this business, i will look into charging more on material but little at a time for me.