@roger,
Roger, I've bought some "as advertised on TV" things I was very happy with as well, but at least one was completely worthless.
What really turned me off was the "style snaps". This one really got me excited when I saw the TV ads because pants and jeans that are the perfect length when worn with heels are too long if I wear then with flats or sandals, and this seemed like the perfect solution.
http://www.asseenontvvideo.com/512220/Style-Snaps.html
I bought them in CVS for $10 for one package--which was in
no way worth $10 given the very cheap materials involved and the amount in the package. And they didn't work! The advesive coating to hold them in place was almost non-existent, and they didn't adhere to the fabric and they just fell off.
Had I kept my receipt, which I didn't bother to do, I would have returned them.
With the Magic Mesh screen doors I'm leary about getting a worthwhile product at a cost of two for $19.99. I do tend to think you get what you pay for with something like that.
I hunted around and found a more expensive version that seems much better made than the Magic Mesh and comes in a wider variety of widths and lengths, and seems more likely to stay up on the door because it comes with a tension bar to support it.
http://www.improvementscatalog.com/imp/10005?cm_mmc=Amazon-_-DoorScreens-_-2012-_-214809&code-macs=MP2XW028&SourceCode=MP2XW028&mr:trackingCode=913185E1-9736-DF11-9DA0-002219319097&mr:referralID=NA
The one above, made by Improvements, is also sold by the Home Shopping Network and I checked out the reviews on their site which were pretty good. As long as you get the correct width and length for the door, they seem to do the job and the purchasers were happy with them. Many people seem to use them to allow pets to go in and out at will.
http://www.hsn.com/home-solutions/improvements-instant-screen-door-30_p-5684170_xp.aspx?ocm=sekw|best sellers&cm_re=merchzone_carousel*page1_spot2_image*merchzones
So, if I buy one of those magnetic-closing instant screens, which I am seriously thinking of doing, I will probably get the more expensive version because it's more likely I'll be happy with it.