If it's for investment find a portable home they're generally free to remove (will cost 35k to relocate and setup/council planning etc). If you're living in it and in all cases really make sure the block doesn't have an easement, underground streams, rock requiring excavation or any other zoning restriction that may turn the project into a money pit.
Not much experience building a home myself but it can end up costing a lot more if you self-manage (ie trying to save money) than it would just to pay a developer for one of $120k upfront basic units (where they organize/are liable all the tradesman). I've heard so many horror stories regarding tradies bailing out unpredictably last minute (no matter how many times you confirm it with them..) and leaving the client 3-5k down here one example if a task involves 2 independent trade companies and one bails out on the 11th hour whilst the other arrives with 10 labourers ready to work on 100k per year, and you have to pay to sit on your front yard smoking cigarettes because the other party bailed and they're unable to do the work... too bad you've already hired them it's not their fault at all and you have to pay them. Unless you can get it all done by the one crew from what I've heard I'd definitely bite the bullet and just get one of those 120k stock units or relative home or be ready for a lot of lengthy vcat disputes. Even heard of people buying homes and having their deeds stonewalled (despite comprehensively confirming) and being 3k out of pocket because they've booked the moving truck, therefore have to pay and rehire it again. So many things I'd definitely have a little bank roll or something set aside to account for unpredictable expenses.
One golden rule is land grows and buildings depreciate therefore I'd personally try and get the biggest block possible within your means and with prospects for good reliable capital growth.
I'm sort've planning to get into something similiar next year, perhaps buy a block in ballarat or wodonga or something for around 50k, put a portable home on it for 35k and flip it for 180k and make up to 100k in only 3 months. It's probably not that simple though! If you're going to manage all the tradies yourself then at least make sure there's no more than one company involved in one task. ie dependant on the other.
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