I know exactly how you feel !
It cost me $100 to take my two to the Groomer.
I have a Clipper Kit, and do "touchups" on my own.
Mainly, it's a very close cut on their undersides, sort
of a "scalp" to allow them to lay down in the cool grass
when we walk/jog.
I also like to keep their Hair clipped short/back from their
butts a little, just so any "debris" won't get lodged there.
My two are little Dirt Magnets/Mudbugs, and don't mind
wallowing in anything that's wet and cool. I keep their
coats short, so a quick rinse with water will get "most"
of the dirt and mud off of them, where they can come
back into the house, without tracking in too much mess.
Even if I were to (personally) give mine a clip two or three
times a year, it still wouldn't be enough practice, for me
to get good at it. Oh well.