First, it's important to realize that Meta is likely tracking you already through its ad-related services even if you don't have an actual FB account. Countless retailers and services are using Meta and Google for ads and analytics and it's virtually impossible to be completely off their radar if you do any online shopping, banking, or service consumption.

Even with the use of VPNs, uBlock and other tools, Meta likely already has your particulars, including full name, phone number, email, and physical address simply by way of family members and colleagues saving that information to their own address books which are then shared to Meta through FB, WhatsApp, etc. In this way, your name, phone number and/or email address has likely already been associated to otherwise anonymized data through retailer back-ends.

That said, if Marketplace is important to you I would simply create a FB account and use it solely for that. I would avoid installing any FB/messenger apps, and opt for a browser-only experience in order to minimize additional privacy infringement. Use FF containers, incognito mode, or a separate browser altogether for FB access if you feel it's necessary.

Meta has taken a hardline approach to fake/obfuscated accounts, so I suggest using legitimate tombstone info but only provide what's necessary for account generation. Anything less and you'll risk a deactivated account, or Marketplace ban.

Don't overthink it. If you use the platform with basic care (no apps, no persistent cookies), then the most they're going to glean is that you like shopping for retro games and other used goods.

Use Firefox to browse it. This addon keeps FB in its own container so it can't read anything from other sites you visit. https://addons.mozilla.org/en-US/firefox/addon/facebook-container/

Then just make a throw away email and use that to make a FB account.

Depending on the comfort level of your spouse, asking them to use their account would be best.

One of the forms of trust in Marketplace is how long the person's Facebook account has existed, how many friends they have, and whether there are photos. If you create a burner account with no photo, no connections, and "Joined Facebook in 2024", you'll have a rough start.

I have had people show up who don't match the account and they say it's their partner or whatnot, never phased me.

If you do decide to make an account, push people to rate your interactions after you make a successful purchase. After 3 messages are sent back and forth, you get an option to rate the seller and buyer. Just tell them you rated them well and would like a rating as you are new to Marketplace.

I do hate Facebook for what it is, but even here in Canada where Kijiji was once king, Marketplace has taken over. I care about the used market (and the positive effects on the environment) too much to pass it up.

You could use a throwaway email and signup for an account. The account creation is a little tricky if you don't use a "real name" but a name generator website may help in this, or use a combination of two tv character names.

Also use a privacy oriented web browser that signs you out each time, something like mule for android or librewolf for desktops.

One thing not to do is use the FB app or the messenger app on your phone, instead do everything on a browser.