Those not on the 40 man or who did not sign FA contracts, they make 2200 a month for 5-6 months. That's probably most AAA players.
Of the 16 positional players listed on milb.com for Pawtaucket, 3 have major league contracts, and another player is on the 40 man. Another 6 hit minor league free agency. Only 6 of the 16 positional players in Pawtaucket are on their original minor league contracts, Ramos, Marrero, Mike Miller, Jose Vinicio, Jantzen White and Sam Travis.
I've tried doing a google search on the average AAA contract and all I can find is the $2200 min-2700 max scale that the original minor league contract abides to, with the note that once that contract expires and players aren't added to the 40 man, they become FA and can barter a better deal for themselves. A guy like Henry Ramos will need to be added to the 40 man at the end of the year. If he isn't and no team offers him a 40 man spot, I'd imagine there would still be multiple teams offering him a minor league contract of varying amounts, letting him get a salary closer to 6 figures than 4. He'd also have a very realistic chance of reaching the majors and all the financial benefits that entails.
It's the guys like Deiner Lopez and Chad De La Guerra that aren't getting paid and probably never will. They end up like Ryan Dent, where they hit minor league FA before they reach AAA. No one wants the services of a AA journeyman, where as a proven AAA journeyman/MLB scrub could be a break glass in case of emergency option for your big league club. Of course, I could be completely wrong and the average AAA player is broke as a joke, but it makes more sense that a team like the Redsox would give Sean O'Sullivan 75k a year knowing their pitching situation than risk losing him to the Brewers by offering $2700 a month.