Like quite a few people I know, I always read the manuals to anything only when I get stuck. Most times there is recourse, like when building IKEA furniture. If you do manager to mubar it then you can always hammer the thing together.
Sometimes though there isn't a recourse like when the Android Marketplace makes the transition from paid app to free app permanent. Put another way, once an app is introduced to the market place as free, it remains free forever.
This is the state as of June 10th 2010. I cant see any rationale behind such a limitation. I am sure it (I would hope) its stated in the Android Marketplace guidelines, but its so counter-intuitive that I didn't give a thought to flipping the switch from paid to free for a single day promotion. It turns out that my promotion has become permanent now :).