If cost is an issue, you might look into TOPS (Take Off Pounds Sensibly). It's a non-profit support group, and for that reason is less expensive. The annual membership is currently $26 a year, and the chapter dues usually run about $4 to $5 a month. Each member gets a weight goal and, if needed, a diet from his or her health care provider. In the absence of a specific diet, the organization recommends an exchange diet--somewhat like a diabetic diet. For more information and the location of chapters in your area, you can check out their website at TOPS Club Inc. - Affordable Weight Loss Support
It's worked well for me. I've lost 30# and am approaching my goal.