Well, all the superclubs are really expensive. €29 sounds quite low actually.
Space on Sunday afternoon is fun and not too full on but very, very Ibiza. Cafe Mambo in San Antonio (which is the VILE area) is fun for cheesey cocktails at sunset. Both of those are cliches, but worth going if it's your first time in Ibiza.
Restaurant wise, I love Bambuddah Grove (where you can stay on and drink all night if you fancy something more chilled than clubbing), L'Elephant and Sa Capella.
Ibiza Town is lovely though, so you're staying in the right place.
If you can, hire a boat and hop over to Formentera for the day. I think there are ferries too if boat hire's too expensive.
It's honestly a lovely, lovely place to holiday if you stay away from San Antonio.