Short answer - alot.
I can tell you how it works in NSW. Every state and network have varying rules, but all in all the process is very similar.
Any work carried out on the network is carried out by approved service providers (ASP) level 1, ASPs have permission to work on network assets. You cannot just ring up your local sparkie, they cant do it and most likely wouldn't know how - working on the network is a specialised area of electrical work.
There is alot of variance in what it could cost. What lines are passing your house, is the area already at full capacity, do you need a transformer. Basically its user pays, if the network needs upgrading in order to carry the extra load of your property then they will bill you for the upgrades.
Are you only interested in bringing the power to the boundry? are you going to want it to come in the property? if so, how far? will you want it underground or overhead?
Any changes to the network require that an ASP level3 (electrical engineer/designer) make a design for the work. Usually an ASP level 1 will carry out the work, there is alot of network involvement that you wont see (and alot of fees for their involvement.) then for a hookup to the residence you will require an ASP level 2 to do the work.
I have friends that went the solar route, they are in a rural area and had a choice of connecting to the network or getting a full solar and battery setup. The cost for both was approximately the same, but with the rebate solar came in less.
Solar is not the easy solution, they really have to watch their load and what appliances they run at the same time, keep an eye on the batteries, which need to be monitored and cared for. Its not uncommon, especially in winter for the gene to be running at night time. At times they regret not just hooking upto the grid but generally they are happy they went solar, but its far from set and forget. The system is about 4 years old and due to some bad decisions and not servicing the batteries like they should, a few weeks ago they had to replace a battery block (2 batteries) and are waiting to see if they have another block that will need replacing - im sure that if they needed to replace both it was going to be about 3K, but dont quote me on that.