My wife is doing the online Weight Watchers point system and I think it's $16/month. She doesn't go to any meetings or anything.
Basically all it does is assign a point value to all foods based on the number of calories, fat content and amount of fibre they contain. You get a certain number of points per day based on your weight and you get a number of bonus points to use throuout the week. So you may get 25 points per day and then a bonus 35 to use through the week as you see fit. Any exercise you do will give you more points for the day, too.
The negatives I see are that while it does promote you eating healthy foods (many veggies are 0 points), it doesn't necessarily promote a balenced diet, but it doesn't promote a non-balenced diet either. In other words does provide the flexability to allow you to eat a balenced diet if you track that yourself. We haven't found that to be a problem at all.
What I've found it's done is shown us which foods are worth splurging on and which ones aren't. We eat a lot less cheese than we did before and we pay attention to which salad dressings we eat, too. Many times we'll choose a lower calorie salad dressing if we want dessert, or skip dessert if we want to drink beer or wine that evening.
Portion control is also a big way to save points. Choosing a 6 oz steak instead of a 10 oz may save you enough points for a couple of beers and we've found that we don't miss (and never really needed) the extra food. It's not too hard to turn one restaurant visit into two meals, either.
As an alternative, if you don't mind tracking more things yourself, you can do the same thing on www.fitday.com
for free. You'll have to figure out how many calories you use per day yourself and what percentage of carbs, protien and fat you want to maintain, so it's extra work, but can be a better planning tool than Weight Watchers. You can also use it for weight gaining if you're looking to bulk up.