Personal trainers can be expensive for most people. At my gym, it's $60 an hour. I know I couldn't pay that every week, and I'd have a hard time justifying it every month even.
If I were rich, I'd probably pay somebody to come over to my house every day and give me a workout tailored to me.
However, since I don't have unlimited funds, I had to find a way to exercise and eat right without paying tons of money. I did this by finding a plan that worked for me and buying into it.
If I would not have stumbled on this plan, I probably would still be out of shape.
There are tons of websites and plans for fitness on the web. Recipe websites, exercise websites, and on and on. It's hard to know what really is going to work.
There are also lots of personal trainers who may or may not be well qualified, but I find that plenty of them lack the skills needed to get somebody on a program they can stick with.
This is mainly because working with someone right there is a lot different than working on your own. For example, I tend to be very focused on any task when my boss is around, and I tend to relax a little when they are not around. This doesn't mean I am a slacker when the boss is away, but I will admit to being a little less mindful of my every move.
When exercising, the only one who suffers if you "take it easy" during your workout is you. You have to have a system in place that keeps you working hard even if nobody is watching. For me, it was using the Body for Life plan. For you, it may be different, but you have to find something that is going to keep you motivated and is simple enough to follow through with.
Think about what you know you need to stay on track, and look for that in your workout program. Also, always go for something that is sustainable all by yourself. You never know when it will be up to you and nobody else to get yourself to the gym.