So I am an Australian and plan on backpacking through South East-Asia for the next 6 months. My travels start in Thailand and I am unsure of what visa to get. I know that being an Australian lets me have a 30 day free visa. 

However I plan on re-entering the country after about 2-3 months from when I leave the country. Will I be able to get another free entry? Do I have to get a multi-entry visa?

If you can help that would be greatly appreciated. 

You get a 30 day visa exempt entry for both your trips to here.

Be aware the airline can ask to see a ticket out of the country within 30 days of arrival to check in for your flight to here.

17 hours ago, order66 said:

Will I be able to get another free entry?

Yes, that shouldn’t be a problem especially with a 2-3 month gap.