commercials are too high for ladders, im scared just going to top of my house
More the reason to have a vac i would have thought. why do it off a ladder when you can do it on the ground?
Cost is not that important to say your life.
But then you need to look at what your business can realistically outlay.
A DIY version as people like to call it, by sourcing the parts yourself could cost you anywhere from £250 for the vac, plus you then need poles, attachments, cabling etc.
on average a house (Just an example) £35 all round... 10-20 houses could pay for what you laid out. a lot quicker than working off a ladder.
Take this - i did a bungalow, 30 metres of guttering FULL of water,moss and silt - all sucked up in under 30mins - 20 mins tidying up - the charge = £40. Now using a ladder that would have taken me a lot longer, got messy through doing it..
As like everything, you need to market the service properly to get anything from it. Oh and the good thing doing it, you will get noticed by the vacuum noise, and get neighbours asking you to do theirs!