I believe this is the La Caracola in Puerto Petro near Santanyi. Keep away from expensive and rather average steaks and go for tasty local stuff like the stuffed squid. Very cheap options if on a budget, lots under €5. Best of all is the lunchtime menu del dia, three corses with wine and water for €7.50. Had a noodle paella as first course, it was worth the money for that alone.