I bought a used electric (Greenworks)from my neighbor for $50.
It works for what I need to power wash a screened in lanai in Florida a couple times a year. Its actually removing some of the paint, so I have to be careful.
The biggest challenge is getting the corners clean because the dirty water pools up. I’m not sure what the pros do about that.
Eventually we might put pavers over the concrete, but I anticipate still being able to use the power washer.