Some thoughts in no particular order:
Check with your city’s park system. Very often they will have workout rooms, swimming pools, or organized sports available to the public for cheap or free.
I concur with shifting more of your diet towards protein. Also, leafy greens especially, and vegetables in general. Don’t like vegetables? Make green smoothies, add yogurt, milk, maybe unflavored protein powder, leafy greens, and a little fruit. Tastes mildy sweet and fruity, even though it’s mostly made up of veggies and protein. Plus, if you think of this as eating “more of” good things, you don’t have to focus on eating “less of” other things. Obsessing over deprivation will trip you up.
Good snacks: Almonds. Get the unsalted ones. You must absolutely, positively do portion control on this – do not bring the entire bag and munch mindlessly, ONLY bring about 1/4-1/3 cup – but a handful of almonds has been shown to keep people full for a longer period of time, long enough to offset the “extra” calories they contain. You end up eating less in the long run.
Speaking of, never eat mindlessly. Calories, often a LOT of them, sneak in that way. Eat on purpose, pay attention to what you’re eating. Don’t eat because it’s there or because you’re bored. Get the junk food out of the house.
This is a bigger lifestyle change, maybe something to ease into, but totally worth it: get rid of processed foods. Get cookbooks or look for recipes online but cook everything from whole foods ingredients. No soda, no ready-made meals-in-a-box, limit eating out. It does take more time and planning (we usually do one or two “cooking” nights a week, though, and eat leftovers the rest of the time). But the big bonus here is that it will, in general, be cheaper to do this. You will also not be consuming preservatives, HFCS, and other non-food chemistry which can cause unpredictable side effects on your body. The good news is that if you stick with this long enough, your tastes will adjust so you will naturally prefer healthier choices, and the consequences of eating crap (e.g. indegestion) won’t be worth it to you anymore.
Don’t drink your calories. Don’t fool yourself that your standard grocery store fruit juice is good for you – it’s so processed that it’s essentially sugar water. You’re better off actually eating fruit. DO drink a lot of water. 2 litres a day for someone who’s moderately sedentary. My trainer recommended that I drink at least 4-5 litres a day. (I usually hit between 3-4 so I’m still working on this.) And yes, during the day, I often pee once an hour. Think of it as an excuse to get up and stretch and move, which you ought to be doing at least that often anyway.
Most important – and this is going to take some trial and error – you need to figure out what changes give you a positive feedback loop. Willpower can get you through for a while, but in order to make this a permanent lifestyle change, you will need to find it rewarding in some way. That’s going to be different for everyone. For me, it’s a number of things: I hate how I feel when I’m prevented from exercising for more than a couple days. I love the performance aspect of circus arts so want to become stronger so I can properly perform them. I prefer the taste of unprocessed foods, and actively dislike processed stuff.
Find exercise that’s fun, which depending on your personality might be group activities or it might be solitary ones – but even if it takes a while to find it, there is SOMETHING out there that you will enjoy. If one type of activity leaves you bored, check out something else. Go swing dancing. Bike. Box. Play ultimate frisbee. Take swordfighting classes. Don’t limit your thinking here, because this is the thing that a lot of people (including myself for a very long time) stumble over. I thought I didn’t like exercise growing up. Turns out school just didn’t offer the right kind of activity, and had they had circus classes, I would have LOVED exercising. Don’t fall victim to this blind spot.
Also, the thing that helped me the most? “No more excuses.” That’s what I told myself everytime I thought I was too tired to get up and exercise, or wanted to revert to old habits. Do I want this or not? If yes: no more excuses. Do it. And I did, and lost around 65 pounds, and aside from intermittent medical issues (e.g. cancer kind of puts the kibosh on the exercise schedule) have kept it off for more than a decade and counting.