Hello Jayne
Welcome to Poms in Oz.
If you can, the best visa is the skilled independent subclass 175 visa because it gives immediate Permanent Residence in Oz together with all the perks that go with that status (eg immediate and full entitlement to Medicare.) Plus it comes with no strings attached. You can settle in any part of Oz, you need not do the job you are trained for and you can simply loaf on a beach instead if you want - you can do anything, anywhere.
However, your Hubby would have to get a positive skills assessment in whatever he works at now BEFORE you can apply for a subclass 175 visa.
If you are thorough, methodical, resonably confident and you are prepared to do a LOT of sheer hard graft, you can work everything out by yourselves, via the DIAC website and those for the various skills assessment bodies.
If you decide not to use an Agent you would save between about £1,500 - £2,250 or so, but that is all, and you run the risk that if you make a ghastly mistake somewhere, you could end up wasting the money you may have spent on the fee to DIAC for the visa application etc. But it really all comes down to how you feel and how complex you think your applicaiton might be.
However, there are so many different possibilities for skilled applicants that the ones who can qualify for a s/c 175 could generally qualify for at least one other visa instead.
Therefore it might be worth having a look at the DIAC website first and seeing how you get on with that. Then maybe have a chat with a few migration agents on the phone. Let them see whether they think you have calculated your points correctly and so on.
A good Agent will not charge for a 10-15 minute chat on the phone and will not try to sell you anything. If you like the Agent and s/he suggests something you may not have thought of, you may feel that you want to use an Agent after all. But I personally would not get involved with the ones who want upwards of £100 to provide a report that does nothing except confirm that which you already know.
I'd suggest starting with the links below and then search through the messages on here about Agents. There is always somebody asking which Agent to consult and they always get lots of replies.
Visas & Immigration
Information Forms and Booklets - Applications & Forms - Visas & Immigration
A-Z Occupations List - Australian Skills Recognition Information
How old is Hubby? Is he still comfortably under 45?
As yet, do you have any ideas about which part of Oz you would like to move to?
Best wishes
Gill