I'm newish at using FC. I've searched for posts about FC and read many but I'm still having a bit of trouble. I'm hoping someone can help.

For example, I receive a FC alert saying UA: PMD-MHT is $198. I click on the link and am taken to a FC page that shows the $198 plus taxes and fees which brings it to $234, available April, May and June. Fine. So I click on May and FC displays the dates this fare seems to be available (Tuesdays and Wednesdays). So I select a Tuesday as an outbound and Wednesday as a return (say April 20-21, for example). Now I am taken to a page that lists the flights available those days and the least expensive flight is $307 on UA. This can't be taxes and fees because the taxes and fees are what brought it up from $198 to $234. Now if I go back and stab at different dates, I can bring it down to $250, but I'd like to be as wise about this as possible. One poster cautioned FTers to remember to read all of the fare rules . . . but my problem is that I can't FIND fare rules until I'm at the booking stage, and the minimum fare it's showing me to book is the $250. Are there fare rules somewhere earlier so that I can read the fare rules for this $198/234 advertised rate and then have an idea from the fare rules what sort of dates to choose?

Thanks for the help.