I'm 27, with stained, crooked teeth, my maxilla & my mandible do not seem to align properly. What's the best treatment? (Photo)

cont'd.... i have quite abit of gap in my top teeth and one gap at the bottom. I also have a stained tooth at the bottom possibly from tetracycline usage as a child. pls i will like an advice on what to do. whether to get braces, invislign or veneers, how long will it take to get result for my case , how much would i be looking to spend to get a nice smile for once in my life and lastly pls how do i address my stained teeth at the bottom. pls help thank you