I'm sending my 18 year old son to Sydney to meet my husband who's on a business trip. So he'll be on his own a lot. They're staying in the harbor area so most things are walkable, but I'm looking for any ticket or tour secrets - where to get cheap show tickets, when is best to visit certain venues, advance discount tickets, etc. Primary interests are opera house, art museums, and anything music-related. Also looking for a good, affordable golf course.

For golf - there are a lot of courses all over Sydney. You might try Woollahra Golf Club, which is open to the public. It's in Rose Bay. You have the advantage that you will be close to the bay and fabulous views and near some really top-end restaurants (one of them, Pier, has just closed and reopened as the Sailors Club), so maybe one to do with Dad, rather than alone:

http://www.woollahragolfclub.com/

From the city, catch the 324, 325 buses in Elizabeth St opposite the Great Synagogue and hop off in Rose Bay (ask for O'Sullivan Rd), walking down O'Sullivan Rd to the club entrance.

Another course close to the city is Moore Park Golf Course. It's not that far from the Entertainment Quarter (also known as Fox Studios), where there are numerous restaurants, bars, a ten-pin bowling alley, cinema, etc. Not sure about buses from the city but there are many buses going down Anzac Parade, or you could possibly do a taxi. A major landmark so you know where to get off is the Sydney Boys High School / Sydney Girls High School.

Lavandula

Oops, here is the link to Moore Park:

http://www.mooreparkgolf.com.au/

Lavandula

Oh, how could I forget - Bondi Golf Club is on the cliffs just to the north of Bondi Beach, and has (weathered) Aboriginal rock carvings. Really a fab location:

http://www.bondigolf.com.au/course.htm

Lavandula

If he is into surfing and even if not, take the ferry to Manly, have a wander, swim or surf. There is a good surf school if he wants to learn. Just google "Manly Surf School".

"Sydney what's on" will give info on events etc during their visit. No doubt your son already has a good idea of what he wants to see & do here from his own research.

The excellent Art Gallery of New South Wales offers free general admission (special exhibitions might carry a separate fee). It is next to the beautiful Royal Botanic Gardens and Domain (also free admission).
http://www.artgallery.nsw.gov.au/
http://www.rbgsyd.nsw.gov.au/

Sydney's equally excellent Museum at Contemporary Art offers free admission, too. It is at the scenic and historic The Rocks area.
http://www.mca.com.au/

Both museums are within a 15- to 20- minute walk from each other. On the way from one to the other, your son can stop at the Opera House.

More suggestions here:
http://www.sydney100.com/free-things...-in-sydney.htm

If he's heading there soon, the Biennale runs through the 16th http://bos18.com/ In addition to the exhibits at the Art Gallery of NSW and MCA mentioned above, there are installations at Cockatoo Island with a free ferry from Circular Quay.

When is he coming & how long will he be here?
There are often special events that we could recommend if we know when he's coming

i think the bondi to bronte walk is great..easy along the cliff path ...safe...for all...although id not do it at night

nice cafes at bronte..and you can walk further on to coogee via the streets...just keep asking the locals

catch the bus from the city to campbell parade which is the big road that lines bondi road
there might even be a gelato store still at bondi...used to be a great favourite of ours but we havent been for a while..used to be in the pavilion area