EXCLUSIVE

The "Vanderpump Rules" cast is pulling in big ratings, but most of them are still drawing small paychecks … TMZ has learned.

Several sources connected to the show tell us anyone NOT named Lisa Vanderpump only made $5K for the WHOLE first season -- but when ratings soared they all went looking for raisies.

We're told the cast wanted 2 things: more money and first class seats on flights. Bravo budged on the cheddar ... handing them each roughly $3K/episode for Season 2, and $5K/episode for Season 3.

But while LV's sipping free booze in first -- everyone else will still be in the pretzel and peanut set. They're stuck in coach.

Much of the cast believes Bravo denied their flight upgrades because execs don't want them losing that working class charm. Most of 'em are bartenders and servers, after all.