Assembly will be hard unless you have all the tools. I spent yesterday arvo ‘adjusting’ the LHS bottom bracket cup of my bike with a hammer and a flat headed screwdriver. Not something I would have done with parts that I actually had to pay for.
Decent 2nd hand roadie from eBay + double sided track wheel = much better value than an OTS POS.
You don’t have to worry about compatibility of parts - and buying a complete bike will always be cheaper than buying parts separately.
This bike I built up a while ago is a good example, IMO, of what can be done quite cheaply. It now has a fixed cog and lock ring on the other side of the hub, and promenade bars.
good point. rode my pub shitter today for the first time in ages: repco superlite with wheels off my fuji track. $80 for the whole bike + whatever the wheels are worth. rides great and cost me just about nothing, so i dont mind locking it at the pub/station/shops. pics to follow 
Go flip flop and make sure you aim to try fixed first and not start on a single, if it’s your bag I guarantee you won’t flip that wheel in its lifetime. The majority of fixed riders don’t trick at all, the appeal is in the riding experience for me.
Also choose the fastest option to get your arse on the saddle and getting some experience, whether that be an off the shelf or your neighbours shitter in his shed. It’ll prevent you dwindling around the idea or losing interest whilst waiting for parts.
As for bad attention?
I only get bad attention when I act like a cunt…which pretty much applies to everything in life.
Good luck
+1
i wanted to build my first bike too but knew it would take me a while to build something/find parts i’d be happy with. i ended up buying an OTS mongoose maurice SS thing for $485 that was by no means amazing (and still isn’t) because i wanted to get on the road asap. over time i’ve changed the wheelset because i wanted to try fixed and at one point i broke 3 spokes in a week!! i’ve also changed the cranks and chainring. probably cost me more than something i could’ve built that would’ve been a lot nicer but i wouldn’t have been on the road anywhere near as quickly.
my 2c.
good luck 
buy off the shelf
up grade parts as you see fit
when a good frame comes along, snap it up
change over parts
put original crappy parts back on ‘first off the shelf’ bike
sell ‘first off the shelf’ bike or make it into polo/pub bike
+1 on the below. A few years ago that’s how we all did it. My missus’ current single speed is my old $20 Europa flipped over to the freewheel (a cheap Shifterbikes 2nd hand wheel). Plus you end up with something that’s, at least, a little bit unique.
That’s a bit alarmist don’t you think? I weigh 80 kg and have done over 1000 km of speedy commuting on my Schwinn Madison with Alex R500 wheels and they’re straight despite skids, shit wheelies and backwards circles and a drunk crash into the gutter while looking backwards.
The Mallet looks like great value, although I’d prefer a drop bar.
yes. you should buy a bike.
go the cell mallet. i rode one and it was brilliant!
i was looking at a rebuilt older bike (60’s frame), but in the end i went for an off the shelf bike (apollo salt).
the things that turned me off were: not knowing the history of the frame (could have fractures, bent, etc), harder to find parts (brakes not fitting due to different wheels), all the parts on a new bike are new, not 40 - 50 years old, no warranty.
if you can, get the felt brougham. very good bike, but it’s very hard to get one as the 2010 factory stock has already been sold, but some places still have them.
if you do get an off the shelf bike, you can still change parts. i’ve changed the seat and removed the rear brake on mine.
i’ve ridden 300km+ on my bike since i’ve had it and the only issue i’ve had was with the sidewall on the rear tyre getting some bubbles, but i’ve replaced that. the wheels take a fair bit of crap due to adelaide’s awesome quality roads and they are still perfectly true
Alarmist? Perhaps… I can only go by my own experience. I bought a off the shelf bike in London a few years back, really awesome bike but riding London streets - which are a bit rougher than over here - trashed my wheels in a matter of months, and I’m only 70kg (AlexRims also). Potholes and skip-stopping snapped heaps of spokes and put flats in the rims. I replaced them with hand-built Velocity Deep Vs with high-flange 36h hubs and quality spokes. Never had a snapped spoke nor have they gone out of true - bombproof. Cost me a bit but were worth every penny I think. In my experience the cheaper mass-produced wheelsets that come with complete bikes are (generally) not that great. Its worth considering, no?
Meh, I’ve had no problems with the wheelset (Alex DA22) that came on my of the shelf bike. By no means a great set of wheels but did the job as I was just getting back into the whole cycling thing.
I think its far easier to get something off the shelf and run with it. Change things as necessary or when you have the cash flow to bling it up. Not that building bikes isn’t fun, I just prefer riding them
I bought an off the shelf masi when i started, just to get on the road quicker, now the only original thing left on that bike is the frame itself.
As you ride and get into it you’ll start getting an idea of what appeals to you and head down that road, but my mechanic skills leave alot to be desired 
I think for your budget and value for money, cell’s more expensive lugged option is sexy, and for a bike under $1000 it’s a winner for me.
http://www.cellbikes.com.au/Cell-Cileto-2010?sc=7&category=12634
This site is one of the best resources
very in depth…
I ride every day to work on a masi speciale fixed.
It’s perfect for what I need. I maintain it myself.
The costs involved are minimal, compared to my last geared
commuter bike that lasted 8 before I had to replace the cassette.
There are a few new bikes for $800, Felt , mongoose, most bikes in this price range won’t be fancy but with the simplicity of a single speed it doesn’t matter.
I suggest getting a flip flop hub to start (most offer this now) as you can
trial both…I lasted 3 days after flipping from fixed to free…yep I only ride fixed now
If you ride in winter there is actually more control riding fixed I find
Good luck
ebay can be yer fiend at times - a mate of mine got a mint hillbrick pista fer $400- not long ago…