...

What does it include?

Timing belt? Brakes? These are pricey and generally essential. Dealers
aren't discounters.

Many, many used cars come on the market at 60K because the owners don't want
to deal with 60K service.

-John

I'm not qualified to make a recommendation, but I don't see why a competent
machanic with your car's service manual can't do it.

One thing I would not do is just skip the service.

As info, my '01 OBW's 30k service included the following (Source:
http://mysubaru.com/). Your car's would probably be similar:

Inspect
Steering and suspension
 
Inspect
Clutch operation
 
Perform
Inspect brake lines and check operation of parking and service brake system
 
Inspect
Brake linings and drums
 
Inspect
Disc brake pads and discs, front and rear axle boots and axle shaft joint
portions
 
Replace
Brake fluid
 
Inspect
Automatic transmission fluid
 
Inspect
Transmission/Differential (Front & Rear) lubricants (Gear oil)
 
Replace
Spark plugs
 
Replace
Air cleaner element
 
Recommended Performance
Replace fuel filter and inspect fuel system, hoses and connections
 
Perform
Replace engine coolant and inspect cooling system, hoses and connections
 
Replace
Engine oil filter
 
Replace
Engine oil
 
Inspect
Camshaft drive belt
 
Inspect
Drive belt(s) [Except camshaft]

30,000 mile service is an important service.  Its one of the major
ones.  Dont skip it!
You first have to outline to us what their service includes for the
$599.  I can say that seems very steep.  I think my dealer here in NJ
was around $400.  There were some "fluff" items I had them not do and
removed their cost from the service to bring it down closer to the $300
mark....which since I am not mechanically inclined was reasonable.

Dom

The 30K service is mostly a bunch of fluid changes and some
inspections, also spark plugs on non-turbo engines. Not worth anywhere
near $600, and it's stuff you can do yourself if you have a place to
work and some basic tools. Otherwise you can have a good local shop do
the work for far less than the dealer charges. Also dealers will
typically hit you up with "add-ons" that are totally unnecessary and
do nothing except line their pockets a bit more.

Look in your owner's manual.  Assuming your Forester is similar to my 02
Outback you are looking at:
Spark Plugs
Drain and Refill Coolant
Air Filter
Change Oil & Filter
Fuel Filter

I did the entire job with a typical toolset in an afternoon and less
than $50 worth of OEM parts.

-Kurt

Do not skip the service items that are listed in your manual. However,
the dealers I have used typically add a lot of other work that the car
manufacturer says does not need to be done. Before committing to the
service, ask your dealer for a list of the items included and then
compare the dealer's list to the one in your manual. If there are
extra items, ask the dealer for a quote on ONLY the items listed in
your service manual. If they will not give one go elsewhere.

In any case, you would be better off with a GOOD independent mechanic
if you can find one. I have a great local shop I have been using for
20+ years. but I know that good independent mechanics may be hard to
find.

--
Vic Roberts
Replace xxx with vdr in e-mail address.

I read the posts and I'm a DIY'er, but IMHO, it's not worth saving a
few bucks with an independent mechanic on this.  My dealer sends me
coupons in the spring for various service items.  I'll bet you can find
a service special coupon from your dealer for this work (check dealer's
website for service specials?).  Dealer service is not infallible, but
it's a safe, guaranteed route.  Read the many recent posts on indie
mechanics screwing up Subarus.  If you know of an indie mech that is
highly recommended and specializes in Subarus, then maybe, but
otherwise it's a big gamble.  Based on your outreach, you don't sound
like a gambler.

My two pence,
LK