yes the price moves up and down.. congratulations you are learning that all currencies fluctuate
however bitcoin is deflationary. meaning over the long term its value per item bought increases to be able to buy more items.
First, how do you know it's deflationary? limited supply doesn't guarantee that. I can give plenty of examples of things that have limited supply and are not deflationary.
Well, bitcoin fluctuate based on hype on meme coins, investigation against crypto exchanges, social networks, Elon musk tweets, and stuff like that - unlike any other fiat currency.