Stick you 8 year old laptop on a platform/table under the lens, get a freebie software and you'll have a perfectly functioning prompter. I've shot 2 infomercials with that method and it works just as good as those contraptions that attack to the lens and cost thousands -- I've used those too.

I don't agree, DP's might notice it if they were tipped off, but those infomercials previewed to a lot of distributors and broadcasters and were televised in many countries and not one single person ever said the host wasn't looking to cam. It passed muster. The only time you need to watch out is on close ups, but that's the time when you have talent memorize a line or two to give straight to camera, then cut back to wider. And a proper, broadcast monitors aren't cheap. http://www.bhphotovideo.com/c/product/582511-REG/Autocue_QTV_OCU_MSP17LWAPP_Master_Series_17_Teleprompter.html.
Were a person that concerned about it, just place a two way mirror in front of the lens, fold down the notebook and now you reading directly to camera. Even freebie softwares have mirror mode. Teleprompter is about the easiest thing in the world to improvise. Of course, is does force one to lock down the camera.

Okay but it's a mistake to suggest to items above are anything remotely resembling a "Proper prompter". They are in fact exactly the type of improvisation that I'm talking about. The smaller one appears to be sitting on TV dinner table! If you want proper, you need something that attaches to the lens with bellows. Also, I can't recommend that second example, 10" would be too small, we used 13" and we were stressing with it. YMMV.
About i-pad, is there a way to remotely scroll? If not, they won't be a good choice for a prompter, you really need to be able to manually control the scroll.

About the socalled Pro Prompters, they can be a headache too, they can place a lot of weight on the lens and tripod, that got us in to trouble nd that's what caused us to improvise in the first place.

Small video about prompter from http://www.ebay.com/sch/sgrovs/m.html

@DrDave

Yep, it is very useful stuff to have.

Here's a quick drawing of my periscope-style teleprompt. Sorry, I'm 1600km away from the item at present...

(Whoops, I should have marked at lower left, "InterviewER or Script"

This is an interesting topic to me as I am building a studio next to my house.
I shall keep my eye on it.

@goanna That's cool concept .. Similarly I feel like fool for not having thought of it.

@brianluce I have to disagree with you. The eye-line is incredible important. While viewers may not be able to comment that the speaker is 'not looking to camera', IMHO, the effect of 'not looking directly to camera' can be taken as insincere or dishonest - why can't you look me directly in the eyes.

@DrDave .. second hand iPad 1.

There must be a ridiculously cheap android tablet that will work. I suppose have a truly monster battery would be a handy feature, plus good BW contrast. Maybe a hacked kindle.

An even cheaper option is to use a longer lens and have the tablet just below the lens using a lighting stand.

I use an 85mm on the BMPC/CC and a first gen iPad. I have a Datapro 300, but prefer the simple under the lens arrangement. The software is a free App and lets you set the text size and speed.

There's https://parrotteleprompter.com as seen on https://www.kickstarter.com/projects/957253584/the-parrot-a-compact-teleprompter-for-dslr-cameras/description .

Parrot 2

https://www.kickstarter.com/projects/957253584/parrot-2-the-most-portable-and-affordable-teleprom

OK, I bought the Parrot V2. It looks just like the picture above. It's small, repeat, it's small--imagine reading from a cell phone. Image is sharp and clear, and there is no light leak or bleed through, as it uses a sealed screw in filter instead of a hood for the back.
It comes with free software for Android and the "other" phone--the software is basic but good: font size, margins, speed, orientation.
I didn't buy the bluetooth remote but for another $20 it might be a good idea.
Minor complaints: the included screw in filters have a lot of paint on the threads, so it's a bit squirrely getting them into the lens. Also, they come in large sizes, if you have m4/3 lenses you will need a step down adapter, no biggie. The 58mm fit my Canon camcorder.
Another minor complaint: the "feet" of the retaining clip sit on the glass of the phone. I'm pretty sure it won't mark the glass, but if you put the phone in a case that has some ridges on the sides (so when the phone is upside down there is like 1-2mm space, good idea anyway) the ridges will protect the phones surface. Verdict: very lightweight, very portable, a good buy, but it is small. Now small is good in that you are always looking straight at the lens, but it's a tiny bit of text. Tip: Add spacer lines to make timing breaks.