I am like this too. Overweight, eat too much crap and definitely can't be bothered/can't afford the gym.
Here’s what I have found the motivation to do so far since just before new year:
Do workouts for free at home on YouTube. I can get YouTube up on my TV. I do the workouts when I first wake up in the morning, so that I can't put it off to later/tomorrow.
Some work outs are 5 or 10 minutes long, so I do those on work day mornings when I don't have much time.
I do ones on a channel called Psychetruth, and they have loads for beginners. Yoga, pilates, kick boxing and all sorts.
I also bought a diary and have been writing down what I eat, when I exercise, and just general ideas, recipes, things to try, motivational quotes, goals, measurements etc.
I have been limiting myself to 2 treats a day. This is a good start for me, as someone who can happily sit and eat 6 biscuits in a go, or half a tub of Christmas chocolates.
I know that I couldn't give up treats altogether, so cutting back is the best I can do at the moment.
Also look for motivational videos on YouTube, with healthy meal ideas and fruits to help you.
I have been drinking apple cider vinegar before meals. Apparently it's good to help you lose weight, and suppress your appetite between meals. I got a big bottle for a couple of quid in Morrisons, and I just stir a teaspoon of it into a big glass of water.
I don't actually know if I have lost any weight yet, but I will weigh myself for the first time in 2 weeks tomorrow. I was hoping to lose 1lb. Going slowly in the right direction I hope.
My advice is not to put it off to tomorrow, or next week or next month. Make a change or a new habit today. Start today. Wishing you all the best, and maybe we can motivate each other on here. 