Hey guys, I have been running off an on for the best part of a decade now. Since the Boy came along a year and a half ago it has been super hard to maintain anything regular (had some surgery before that as well, complicating it further) but there is no doubt in my mind that I have more energy (well, energy at all is good right now!) and feel better in myself when I manage to get out and run.
For those that are worried about being slow, or not being able to go far, the couch to 5k has been mentioned in here. As well as that, I cannot reccomend Parkruns enough. They are friendly, welcoming and you can walk the 5k if you want. Plus, for those with older kids, many places do a kids Parkrun on a Sunday, so you could run with your child/children together. They have them all over the place (I am in Surrey and have five withing 30 minutes drive, and I recently did one in the Lake District whilst up there on holiday).
And it is 100% free: