If you have a very old smartphone or no smartphone and you want to watch your budget then a used or refurbished phone should work great, try to get a model that came out in the last 16 months and check the camera specs before buying it.
If you want to edit your vids, you can edit on smartphones or tablets too, though there’s sometimes advantages to working on a computer. For iPhones you can use the free iMovie app, but there are plenty of options out there. Feel free to check the App Store or Google Play App store for the application that suits you best!
If editing is not something that you’re into, you can also opt for the easier style vids and just hit record and film everything in 1 take, start to finish with no cuts. You are unique and your content is too so anything you create will be awesome!