Tried searching the board … no luck.
Do they (comparison sites / airlines ) really hike the price after a few attempts of searching?
That happened to me on more than one occasion.
Does it happen routinely ?
Kayak would be a perfect example, or trivago (hotels).
I clean cookies after every search… doesn’t help anymore.
I heard they now monitor not just cookies but my IP address as well.
What has been your experience?
Looking at the stampede of people willing to answer
it feels like my question was really stupid.
Oh well.
I never buy through travel comparison sites. I compare through travel comparison sites. I then go buy directly from the airline or hotel website in a different browser.
Check out an app called Hopper. I read about it, sort of a comparison, plus predictor of airfare movement, up or down, how substantially, etc. Claims insider access to pricing strategies, etc. Even having read about it, I could not find it at the App Store. (May not be the case for you!) Eventually finding a link from a blog!
It’s a very interesting tool, give it a try.
(Definitely was NOT a stupid question!)
I asked the same question a few months ago! And got the same response-not much.
I certainly get the feeling that if you keep searching for the best price, those initial prices are not there when you go back.
I now have 2 rules: reserve the first good price I find, I count on the 24 hour cancelation policy, before I continue shopping. 2) keep my cookies cleared while I am shopping. Certainly when I go back, my browser is brand new. 
Seems to work for me, especially rule 1.
You could also check out a site called, Skiplagged.