I honestly don't know about these self cut apparati, but I do remember thrifty friends of mine going to barber or hairdresser schools for cheap cuts. Some time ago, a friend came to work with the back of his head shaved but the hair still longish in front, he looked like a monk or some kind of looney...we all poked fun at him, but his triumphant reply was that he only paid $2 and was so much smarter than people who paid $8 or whatever. You would have had to pay me $1000 to walk around with that hair. My wife took my daughter to a hairdresser's school once and our little girl did not forgive her for that for some time, luckily it was in the summer and not that many of her friends saw her...even the wife stopped going there for herself after that.
I go to cheapo salons that are $12-14, tend to avoid barbers because I have always had better luck with hairdressers actually cutting it the way I want...barbers seem to me to have their own way of doing things and don't listen so much. I get it cut fairly short and let it grow out for 3-4 months, it gets a little shaggy but I used to wear my hair really long and am comfortable with it. I usually close my eyes when they spray my head before the cut and then just keep them closed, partially to relax and partially to avoid the inane chit-chat.