While I don't know anything about weight loss centers, I do know what it's like to feel frustrated. As I recall, you're in my age bracket, and at this point in life, I don't think giving up is an option if you want to be healthy. As others have said, what will giving up get you but more of the same, and, frankly, I'm betting you're tired of that. In the scheme of things, does a few pounds difference on a scale really matter? If the number is important, then choose a scale and stick with it. (It has been important to me--important enough that I don't weigh at my doctor's office ever so remember that you can just say NO when they ask you to weigh in.)
You don't need motivation; you need commitment. I imagine you're committed to brushing your teeth each day, to paying your bills, to going to work if you work outside the home so make that same kind of commitment to losing weight. Don't make losing weight be about a certain date, a certain scale, a particular type of food--just start eating right and exercising now. If you feel like you want to spend money on a weight loss center, then go for it, but remember that programs only work if you will do the work.