Before Christmas I was looking for a shortdot for my rifle, ie 1-4x. I looked through a lot of scopes and my conclusion was unless I spent £100 or so I was going to have a lot of parallax, colouration and other problems, not least of which was often they were more like 1.5 or even 2x at the lowest magnification. So I ended up buying a real steel Bushnell which was about £120 IIRC. Its very clear, about 1.1x on the low end and has good turrets you can get to and move with your hands for adjusting zero. I know why people don't want to spend that sort of money, I wanted to spend £40 as well I just couldn't find anything I was really happy with at that price point.
I view this the same as laptops, you need to take yourself down to Pc World and actually use a £400 laptop, just open up notepad and start typing and compare that to the £1000 one next to it and you'll see the difference immediately. Go look at some scopes in a gun shop and an airsoft shop and you'll determine if you can live with the problems of the cheap ones or not.
A great example for me was before the shortdot I was looking at the 3x flip to the side in pro airsoft. Turned out the eye relief was really small, to the point where I thought it was likely my goggles would interfere! That put an end to that possible purchase in an instant. Wouldn't have realised how bad it was unless I tried it. I think its the way to go because without experience of a decent scope its hard to evaluate the airsoft one other than "works".