Yes yes yes, I know no one should be fucking using windows go on TOR but tbh who the fuck is bothered to shut down their computer and boot up TAILS everytime just to see some listings and possibly talk to some venders.
The only time when I boot until TAILS is to access my electrum/tumble/buying shit. Or I haven't started up my computer yet and want to send a few pgp.
So is it okay to talk to venders or check on listings whilst on Windows?
You're fine. TAILS is great but for the average customer not necessary, although better OPSEC never hurts.
As long as you don't send coins directly from exchange (eg Coinbase) to market and use PGP + updated Tor with NoScript enabled then you're good