Hey Sooz, I started a few months back, took out a year's membership (via work so got money off!) with our local council's health membership, and it only works out at around £24pmth and I can use any gym in town (around 4 or 5 I think) and go to any council run keep fit class, which there are loads of, and use the swimming pool.
I go to a keep fit class at our local pool on a Monday, Wednesday and Friday and go to the gym for half an hour on a Tuesday afternoon whilst my wee boy does his football training indoors at the centre, so I defo get my monies worth as to pay for it individually would cost me around £15 a week! Plus buying the membership for the year means I will go each week as I hate paying for something and not using it and if I'd paid monthly by direct debit, I'd be tempted to simply cancel the DD and stop going!
Other than my classes and weekly gym visit, I try to walk up to and from school twice a week to collect my boy with my little girl. It's all up hill there and I'm glad it's downhill on the way back! It takes around 25mins to get there but a bit longer on the way home as the kids tend to "muck about" on the way! But at least it's better than sitting in a car. I'd do it everyday if I could, but with after school acitivites three days a week it's not possible with times etc.
Good luck in whatever you decide, it's a positive step forward and will really help with your weight loss!