PC halfway done

I hear most people with more PCi cards like double Video cards and more have double or multi PSU rail. AS for me, just one Video card so sounds like i should stick with a single PSU rail
Hardware https://i.imgsafe.org/bca0787fe1.jpg AMD fx 8350 not included yet
Case https://i.imgsafe.org/bca901300d.jpg

Don't worry about things like PSU rails and the like. Just make sure you get a decent PSU with enough power for your rig. Read a reputable review (here on Toms are okay, Jonnyguru.com also do fantastic PSU reviews). Let the electrical engineers that design PSUs worry about how many rails they have and all the potential complexities that those questions bring.

All that matters to you is that the PSU provides enough power for your system, and it does so reliably.

If you want some specific recommendations, post back with your current build (just CPU + GPU is probably fine), whether you want to OC, and whether you have any future upgrades you want enough power for, AND your region or preferred shopping site. I (or someone else) can have a quick look and suggest a unit or two that should serve you well.

what current build, do u want a list of what i have. I can't put it together without the psu

I was answering your question with a general principle: get a quality PSU with enough power.

I was then wondering whether you wanted some specific recommendations, because it can be very time consuming searching for and reading through PSU reviews.

To make a suggestion I need to know what the PSU will be powering, and which country you live in/what shops you buy it from.

I see you've updated your post with the components. So unless you're looking to push that CPU really hard with a massive overclock, a good quality 450W PSU is plenty for what you have.
Are you based in the US? If not which country and what stores do you get components from?

The newer Corsair CXM units are really solid and often well-priced (they have white writing on them, the older ones with green writing should be avoided). But it depends what the prices are where you shop.

Ok, I live here in the U.S and I bought a few hardware from Amazon.com and the rest from Newegg.com
2 HDD one now and the other later
2 sticks of 8Gb Ram
1 Geforce 1050Ti video card
LG dvd/cd combo
AMD-fx 8350 cpu
970 MSI M/B
Coolmaster Heatsink Hyper 212 EVO
PCI wifi card
So i figure with one Video card, i just stick with a PSU with a single rail, just what size watts would i be needing.I look at newegg calculator and get 516W and other calculators i get less them 516W SO would a single rail PSU with 600W work. that's all in the list that i'm adding along with 6 led fans
The Video card says (300W or greater power supply.
PCI Express, PCI Express 2.0 or PCI Express 3.0 compliant motherboard with one graphics slot https://www.newegg.com/Product/Product.aspx?Item=N82E16814487291

Oh right, I didn't realise you were in the US. That makes it easy...

Just get this 520W Seasonic for $45 (50 if you can't use the MIR): http://pcpartpicker.com/product/fZyFf7/seasonic-power-supply-s12ii520bronze
It's a really old design now, but super reliable and solid. Unless you're overclocking everything to the hilt, or intend to upgrade to a beastly 250W GPU in future, 520W is all you need for ever.

*update -> like I said, don't worry about the rails. Just get a decent PSU and you're good to go.

Example: if u got a little bigger PSU like a 450 and u get a 550W PSU, will just 450W be use from the wall and the rest just not in use.
What is a good PSU brand and What is a good 80+ I read that 80+Platinum is the best and the gold is the second best

Well I've suggested a good PSU for your build. But if you're interested in understanding things I'll have a go at explaining it...

So you understand that watts is a measurement of power? The job of a PSU is to provide the computer with as much or as little power as it needs. So at idle, my gaming desktop might need only 25W or less, and the PSU will provide it with that. It'll provide that 25W to the computer whether it's a monster 1600W PSU or a tiny 200W one... whatever it is... as long as it's working properly it'll provide the computer with the 25W it needs. When I fire up a game my PC might all of a sudden need 400W, and the PSU then needs to provide that much power. Obviously the 1600W PSU can do that just fine, and will still only be operating at 25% capacity, while the 200W unit will fail. Quality PSUs are built with a range of safety and protection features, so a quality 200W PSU in that situation should just instantly power the computer off without damaging anything. A poorly designed unit however could fail catastrophically, damaging or destroying any and all components in your computer, or even start a fire.

Point is, irrespective of the wattage of the PSU, while it's working properly it will deliver the computer with as much or as little power as is needed.

The related issue - which also leads into your second question - is about efficiency. In order to provide your computer with power, the PSU has to convert the power from your wall socket (AC 110V or 220-240V depending on where you live) to the correct power that your computer components require (a variety of DC voltages such as 12V, 5V 3.3V). However, there's no perfectly lossless way to do this, so in providing those voltages, the PSU always wastes a little bit of power. Most of that power is lost to heat in components in the PSU, which then needs to be dispersed with heat syncs and airflow from the PSU fan so that none of those warmed components ever get too hot.

Point is, a small amount of power is wasted by the PSU. That waste heat is talked about in terms of efficiency. So the more efficient the PSU, the less power it wastes to heat... (and that means it runs cooler and requires a slower fan, or even no fan at all to keep temps in check).

So back to my example, at my 400W gaming load an efficient PSU might be pulling 440W from the wall to provide the computer with the 400W it needs, with ~40W (~10%) wasted to heat. While a very inefficient PSU might be pulling 480W or even more from the wall to provide the 400W, with 80W (~20%) wasted to heat. However just to be clear, both PSUs would be providing 400W... efficiency just relates to how much power is wasted by in doing so. The 80 Plus standard is a measure of efficiency. Google it if you're interested in the exact specs, but essentially it goes from 80+ (blank), to Bronze, Silver, Gold, Platinum, Titanium. Higher tiers are more efficient.

Final point and then I'm done: PSUs tend to be most efficient at around 50% of their maximum load (whatever that is). Also, they are often quite inefficient at very low loads. This is why it's generally not a good idea to get a stupidly overpowered PSU. Because it'll be running at a tiny fraction of it's load making it (usually) very inefficient. Take my example above of the 25W idle load. In that case the 200W PSU is operating at around 12% load, while a 1600W PSU would be operating at less than 2% load. It's actually likely that a "less efficient" 80Plus Bronze 200W would unit actually be wasting less power on that 25W load than a theoretically much more efficient 80Plus Titantanium 1600W unit would.

Point is, don't go overboard on wattage... you'll just waste power for no reason.

Having said all of the above... unless you live in an area with exorbitant energy prices and game for 8 hours a day, it's not really going to make any significant difference to your energy bills.
ALSO, efficiency is actually much less important than getting a reputable and reliable unit. i.e., one that's going to provide nice stable power and not cause instabilities, set itself on fire or destroy any of your components...

So, I go back to my original statement, all you need is a decent ~500W PSU. I'd recommend the Seasonic I linked. But there are other good options too.