Not a smart man? Yet you post a question cleaner than most millennials can, and you didn't have to use any memes to get your point across. You're doing alright. They can't even get it right these days talking-to-text their way through a 4 word sentence.
If you like doing woodwork with your dad, DIY subs are fun and satisfying to build. I built my first Ultimax for less than your budget, including the amp to power it. You can look around here at speaker and sub kits from
Parts Express, and there are other forums about the net that have a lot of information on building and proven designs.