you seriously make me want to go vegan but i havent a clue where to start :[
That's great! I'll see if I can give you a hand with that!
Food-wise, it's not too hard. Here's what I did, and I've been vegan two years now, so it seems to have worked okay.
Replace cow's milk with soya/almond/coconut/hazelnut/oat/rice/other milk. I use soy because it's cheap and readily available, but almond is my favourite. Tesco has soya milk for 59p a litre, whereas other plant milks can be £1.60 a litre, generally.
Buy a few vegan staples. Rice, red lentils, pasta, assorted varieties of beans, chickpeas, and oatmeal. Buying bulk dried (or tinned) stuff is way cheaper.
If you can afford to buy nutritional yeast, do so. (it's great) Some brands are fortified with b12, so buy this if you can, and if you don't have a source of b12 through fortified foods you should get on that.
It's also a great idea to buy fruits and veg you enjoy and can afford. Green leafy veg is a must, like spinach and kale and cabbage. Other than that, aim for a range of colours.
I would consider seitan, tofu, and processed faux meats and cheeses to be luxuries, and I don't buy them, but if you find good prices there's no reason to avoid them. Sometimes I get nice yoghurts or custard or Linda McCartney sausage rolls and they're amazing.
Find a few recipes you really like that are simple and not very time consuming, and spend a day making them in bulk to last you a week or so. That way you'll always have something to eat and won't be tempted to break vegan for convenience.
Some people throw out or donate non-vegan clothes (wool, fur, leather, silk, etc) to charity, but the main rule is to not buy any more of these items.
Commercial toiletries, cosmetics, and other products, can be tested on animals. PETA has a list of companies that don't test, and this is another good website I use. Alternatively you can DIY your hygiene and cleaning products, which can often be cheaper as well. I've made my own toothpaste, deodorant, and face-masks.
If you have a smartphone, animalfree is a super helpful app that helped me learn and check for less obvious animal ingredients in foods and cosmetics. Barnivore is a website that's also useful if you drink.
I don't think I've forgotten anything, and I really hope this helps. Send me a message if you've any other queries, and good luck!