JMP you pay to your account and then they charge it monthly or as needed. For instance the numbers are $5/month. I auto load $15 whenever it drops to $5. You can adjust the amounts and timing but there is some minimum I don't remember. For data, you prepay for it and then you get charged when it runs out. JMP is privacy friendly and doesn't really need any info on you at all. I forget their payment methods but that would essentially be the privacy gap. They are US and CA only so no international travel. They are also VoIP which has its own strings attached that has nothing to do with JMP as a provider, just with the VoIP platform.

I still have a number with JMP but have recently moved to Cape for my primary number. They are US only (so again not international) but seem as private as you can be with a standard carrier. They don't need all your info and they don't store your payment info, though there's no "purse" functionality, you just prepay for the month. I really like some of their features like rotating IMSI number and secondary text only numbers. There's a referral program so if you sign up with my code we both save $20 off our bills. Referral code: GCMHTPE2

Pretty much every supermarket near me sells prepaid phones. And yes, they work exactly as you described. You buy minutes or data to add to your account, and then it sits in your account until you use it. Before the memory shortage price gouging BS, I could go get a burner phone for like $75 at my local Walmart or Target. No clue what they’d cost now, but they’re likely still pretty cheap as far as phones are concerned. The phones won’t have great hardware, but they’ll at least be able to run Android and can do all the things that modern smartphones can do… Albeit much slower than a flagship model.

As far as privacy goes, that will largely depend on your local laws. Drug dealers have historically used prepaid phones to avoid being tracked, (buy a phone card with cash, so you never have to use a debit or credit card to pay,) so governments started passing Know Your Customer laws that require the phone companies to verify and log your ID (tying it to your prepaid phone number, the same way a regular phone bill is tied to you) before they can sell to you. That way when the cops subpoena the phone company to see who owns a specific phone number, the company can actually tell them.

Thanks all! You can still get prepaid phones for less than $75! I did pay a bit more for a 2nd hand Pixel to try out GrapheneOS. Signing up to a carrier seems to be where all the PID info is collected (and where they make their money). I checked a handful of Walmart's carriers websites, and they all only had monthly plans, but there might be something different if I visit and ask in person.

I've seen Cape come up a lot and it looks great, it's just pricier than Phreeli.

While mobile data is the biggest need for the OP phone, the JMP/Snikket/Cheogram combo sounds like a good solution for a work number I need to setup soon.