Well, you get what you pay for. Cheap or free stuff usually has a HUGE ASS caveat attached.
Well, you can live a privacy minded life, but that takes work.
Root your phone. Ideally, install a custom ROM you can trust (lol). Rip out the google apps. Rip out any preinstalled crap. Freeze any processes that refuse to stay down using e.g. Titanium Backup. Grab a copy of a privacy minded messenger (e.g. Signal, but don't use their profile stuff), install and configure a hardened browser (that's a week's worth of tweaks and tutorials on its own, hint: most likely no chrome based browser, and even mozilla is after your data like you wouldn't believe). Don't even think of using a free email address and email program. Disable most functionality by default, like GPS, WLAN or the wireless data connection and use it on an as-needed basis. Scrape any file you send from your phone for data (most blatant example, EXIF and GPS data in images). Use a prepaid phone contract and occasionally switch providers. Create a VPN to your own home, don't trust paid or free VPNs. You can still use them going from there, just don't expect them to actually do anything.
Or just get a "feature" dumbphone and get a small form factor lappy like e.g. a Dell XPS 13" with an at least slightly hardened Linux or a rooted and sanitized tablet.
Also, lol, social anything. If you install or use those things you might as well not bother.
It's a lonely life being your own man/woman.
Honestly though, even a little bit helps. Disable third party cookies, install ublock Origin + umatrix, privacy badger, cookie autodelete, decentraleyes, disable remote fonts, and spend a bit of time properly setting up your browser so that it doesn't leak your data like a sieve (e.g. by disabling WebRTC, enabling the fingerprint setting in about:config in firefox and wiping local storage, cache and cookies at least every restart). That's as good as you can get "on the cheap". Don't use any dedicated social media apps and rely on your slightly hardened browser to protect you. Kinda, sorta. Better than nothing.