Fast growing screening hedge recommendations

Oh dear, oh dear. When are people going to understand that plants are growing things and take time! It doesn't matter if they are growing at your place or the nursery - they all take time. And that is why you have to pay a lot for larger plants - they've already taken years of nurture to get to that size.
Lythande is correct in stating that the faster they grow - the higher the maintenance required. A good hedge, full all the way from the bottom takes years of regular maintenance and clipping to keep it tight and tidy. You do, however, have differing options that, although the initial outlay might be greater, require far less time in maintenance - they are called fences. I suggest this might be your better option - given your propensity for impatience. And might I also point out that large grade plants also take more than their fair share of maintenance in the initial stages. Given that they are pot grown and generally top heavy, there is a good chance that they will suffer root ball rock whilst trying to establish. They need to be well stabilized, watered with unending patience and if you are not prepared to look after them well, you might just as well burn $100 notes. However, there are several plants that will give you good value for money, insofar as you can buy good grades for a reasonable cost and are relatively trouble free. The small leafed pittosporums, like Mountain Green, Limelight, Wrinkle Blue etc, Griselinia littoralis, then the good old camellia hedge - sasanquas are a good option but check on hedging varieties, and also things like Prunus lusitanica. Other things that form good hedges (but need regular clipping) are hornbeams and european beech (green or copper) but they are deciduous. Mind you, they mostly hang onto their leaves until the new ones develop so you do have a brown hedge for part of the year. Other options could be to put up a relatively open framework for a fence and grow climbers on it or even a relatively cheap fence, like corrugated iron, painted a very dark green (so it forms a background only) and either plant specimen trees or attach something like trellis panels and place a large pot or water feature in front. The possibilities are almost endless and really don't need to cost a fortune - they just need imagination. The other thing I would point out is that you have chosen just about the worst time of the year to want to do something like this.

Thanks so much for the advice and ideas. I'm not going to do it just yet i was thinking may be autumn but i need a plan of attack and to save my pennies. Will check out the types of plants mentioned above

Im looking to plant some sort of screening hedge to give some privacy from Neighbor's. There already a harden there and i need to cover about 8m in length.

Is there a fast growing/low maintenance hedge, that once it reaches its full hight 2-3 it slows down and is low maintenance?

I say fast growing because i dont want to spend a fortune on ready grown large plants

Fast growing = weed.
You'll have problems later. better to have patience and do it properly.

you will need to buy trees already at 1.8 or 1.5. nothing is fast growing. its taken about 4 years for my pittsporum to get to 5 metres. had i of know it would have taken so long i would have invested in taller trees to start off with. there is a 1.5 wooden paling fence along the 10 metre boundary, i put 1.8 metre brush fencing ontop of that and planted .5 pitts infront at .600 centres. its now a trimmed wall of 5 metres high about .600 deep. unfortunately the housing corp tenant took to it with a machete on his side but inside my boundary and denuded the middle of it. on the suggestion of an arborists we topped the pitts by a metre to force new growth back in the centre. and its working with heaps of little leaves filling in the gaps, within about 6 months it will be a solid wall again.

Anyone know where I can get 1.5m plants for a reasonable price? I was hoping for portwine magnolia, but they seem to $150 + per plant and I think I need about 7 plants or more