I'm not a cook. I like to eat pretty soon after I feel hungry, and don't enjoy prepping or cooking dinners. I've had to figure out ways around this food apathy, and here are 3 items I've bought which have helped me eat well since I improved my diet.
Not technically an appliance, but definitely my favourite - I bought this Sistema 2.4L Medium Microwave steamed from TK Maxx, but I've seen it in Tescos and other regular places. It was about £6 and honestly I couldn't rave about it more.
Ignore the fact that I had to buy a microwave in order to start microwaving vegetables (I'm presuming most people have one already!), this little plastic box has been instrumental in me eating so many vegetables now. It enables me to cook a whole pile of veg, super fast, but keeping them fresh and crunchy (not boiling them to mush). I can have a dinner ready in under 5 minutes which suits me perfectly!
My mini slow cooker from Wilko was £10, and got me through the colder months. I needed such a small one as I live alone and don't have a freezer to store left overs. I could whack in veggies in the morning, and they'd be ready as soon as I wanted dinner. I have also used it to cook certain foods faster; got home from work, shoved some food in, popped to the gym, and returned to eat it. Quick and healthy!
My sports headphones have been a gym lifesaver. You can run without constantly needing to adjust your silly normal headphones to stop them falling out. Mine were maybe abut £17, but they're definitely available cheaper.