Bought one of these for the same reason mate, better safe then sorry. Just have to make sure you've got your arm at the right height (heart hight) otherwise you'll skew the reading and end up a hypocondriac checking and rechecking lol. Mine came back in 140/90 range a few months ago, cut out the sodium and forced myself to drink 5ltrs water a day, now it's steady 120/80 +/- 2 points.
Considering the side effects of the running multipul compounds and the money spent on these compounds over the years, $100 bucks is a cheap investment towards ones health.