How much personal training do I need? Is it worth it?

I just joined a gym, which I’ve pretty much never done although I have worked out in the past.

Naturally, the upsell is personal training. If I had the money, I’d do it, but nowadays I also have a decent credit card balance to pay down.

Even so, it seems worth it to get started training properly and effectively. I suppose the other option would be to research how to train online and put that to use.

My plan, by the way, is to go at lunch so I can get away from the desk, computer, and extended periods of sitting. Basically, my schedule is such that I can go every weekday. There’s a pool in addition to machines, weights, and cardio.

What would you recommend? Number of sessions? ½ hour vs full hour? Other resources?