Check where each band actually lives before you compare two quotes. The Illawarra pool is real but modest, and Sydney bands will happily come down the M1 for a Saturday, which means one of your numbers may have an hour of travel built into it and the other may not. Ask the question directly rather than reading it off a listing.
The other local wrinkle is that Wollongong has a proper club and RSL circuit, so a lot of these bands are used to a room with a stage, a house system and somebody who runs it. That is a far simpler night than a marquee on a property up the escarpment, or a surf club with one power point and good intentions.
Top picks are the acts in this category in Wollongong, without a review, rating or premium ranking: all these sort keys are tied.
Some are and some are Sydney acts willing to drive, which is fine as long as you know which you are looking at. A local band can do a site visit and a late change, while one coming down for the night is committing to the M1 in both directions. Ask each act where they are based and where the players live, because a band with an address here and a drummer in the inner west is really two answers.
Lineup size first, then hours, then travel. Three players doing a couple of sets in a club room and a five piece covering a full reception out at Kangaroo Valley sit a long way apart, and the second carries the drive as well. Each starting figure here belongs to that band's smallest version, so find out what the bigger one costs before you fix a budget.
Regularly, and the two things that decide it are power and cover. A full band with lights draws more than the single circuit a marquee is already running, so confirm what they need and who is hiring a generator if the property cannot supply it. Have a wet weather position agreed and named, since a storm coming off the escarpment does not give you long.
Two or three months is comfortable outside the peak, and a Saturday between October and December wants longer than that. The pool is small enough that a late enquiry often means widening to Sydney or down the coast, which changes the price rather than the standard. Send your date to several acts at once instead of waiting on each reply.
A club function room in town and a farm at Jamberoo are two different jobs once a loaded trailer and a late finish are involved. Give the address in your first message and the figure that comes back will hold.
Clubs along the coast usually have sound rigged and someone on it, while halls and marquees have nothing at all. That difference changes the setup time, the price and sometimes the lineup the band recommends.
An afternoon southerly off the water will take a speaker off its stand and flatten a vocal. If the reception is outdoors near the coast, agree a sheltered corner and who makes the call to move.