Standard lots around here are 80 x 125 or roughly 10,000-sq-ft. Open lawn (no fence, swing sets, trampolines, etc.), and no dog poop or kids toys, yeah, I'll do it for $30. If dog or toys, I charge $35, and if it has a fence I will charge $40. Have a small 36" gate, and it could go up again. I have some customers I charge as much as $65 for their 10,000-sq-ft lot. I even have 1, just 1, that I charge $95 because its a lake front, its one continuous slope going into steeper slopes, and I have almost killed myself cutting it.
Grass was a little wet, and once it started sliding, I couldn't muscle it or power it to safety so I had to jump off and I slid on my ass down the 30-feet 60°+ slope, with my eyeballs popping out of my head and my heart going a 100-mph.