I spent $8000 for trenching but I had a 24" trench dug 485' starting at 44" and ending up near 9' deep at septic. Mine was a multi use trench that got electrical conduit (3"), 1" water line and 4" sewer. This included backfill.
3" electrical conduit is a million dollars these days...
Just had Gingerich Structures (Formerly Farm & Home Structures) build my 50x70x16. Their build crew was all Amish and they were fantastic. They work in Missouri, and I can't recommend them enough. So great to work with. The lake community I live on had QSI build a shop for boating equipment...