Costuming is VERY personal. And people get into it for personal reasons. My best advice: pick a character you're passionate about and learn the skills necessary to make that costume.
Your first attempt will not be perfect, accept that now, but by doing it, you'll gain the skills and experience to do something better the next time. And THAT is why it's so important to pick something you're passionate about rather than just something easy, because something easy ALSO won't come out perfectly your first time out. So it's better to have something imperfect that you're passionate about, than something imperfect you're not.
So, maybe if you tell US what costumes you'd like to attempt, that really inspire you, that you are really passionate about, we can point you to resources to help you create a piece of that dream!
Money will play a big part on how good your costume is going to look in the end. You can start off by using EVA foam for your build... It is cheap and comes in various sizes and colors and and reading up on other costume builds on here can help as well. Start with a character that you like, something simple so you can get used to the tools and materials. Good luck and have fun. Don't forget to post pics.
Have a picture of what you want, have multiple pictures of what you are creating, and have them available while you are creating. Work with whatever medium you feel comfortable with. Take your time. Don't be afraid to start over. Make things in sections. Try to make a paper template first, then it becomes cut n paste. NOT ALL TEMPLATES ARE CORRECT. They are close, but do not go for a final product before testing it first. See attacked Starlord nasal bridge
Starting with something simple is a very good way to start. There are some great tips here, but not knowing what character you are trying for, I'd suggest checking out the thrift stores and find what's available that would be off the rack and you can modify into that costume. These are a great source for non-superhero type characters.
All i can say is do a lot of reading, research. Use the search bar. Youtube tutorials. Shop around for the best possible price. Measure twice, cut once. Use the safety equipment required. Read and understand the instructions. Best of luck and have fun doing what you love...GM
You are the onlyone that can decide for sure what is a good character. Don't just make something because someone else thinks it's good. If you enjoy a film, or a character from a film especially and like it enough to make a costume from, then put your all into it, even if your budget is low. Be creative with what you have to work with. If you have cardboard and foil and tape, use it. Make something. Do something. Asking for hints and characters won't help UNLESS you have an idea of what it is YOU want, and then others can offer some advice from there.