I have a few ar's and I want to add a few ww2 era rifles to the safe. I know very little about older military rifles. Looking for a cheap range toy. Also want to be able to find cheap ammo. What would you suggest?

Mosin Nagants....lots of them

This.

Look at site sponsors, estate sales and pawn shops. Check out Gunboards for more info beside this great forum. Research as much as you can so that you know what to pay and what you are getting. I've seen more than a few new collectors get ripped off and discouraged because they didn't research. Buy the rifle not the story. If you can, take a friend who collects with you when you buy or ask some questions here. Whatever you buy stock up on ammo when you find it cheap or get into reloading.

I've been at it for a while the only thing I wish was that someone told me how addictive these things are.
Good luck.

Edited to add while not cheap, a CMP Garand is a great value. Might want to look into one.

I will give you a top 5 list that will get your foot in the door that will be both affordable and iconic of WWII.  Please note that these will not be pristine and may not have matching numbers but are a perfect start to get into collecting.

1.) as others have said would be a Mosin Nagant.  You should be able to find these all day long for $150.
2.) some sort of Enfield, preferably a No. 4 as these were WWII used and still able to be found in the $200-300 range for a non-matching run of the mill specimen
3.) a German k98 Mauser.  I may catch some flack here because it is easy to spend $600+ on a k98.  I will not tell you to do that.  Take a look at J&G sales.  They have German k98 Mausers for $250.  Granted, they were WWII captured rifles that had the Nazi markings penned off, a Yugo crest added, and maybe a new barrel, but at the end of the day it still is a German k98... more or less.
4.) a M1 Garand from the CMP.  This is the most spendy at about $700, but a collection would not be complete without it.
5.) A Swiss K31.  This is the odd ball because it was not a war used rifle due to Swiss neutrality, however it was a contemporary of all the above.  It will also likely be the most accurate and you will not regret getting one.  Priced about $350

Honorable mentions would go to a Japanese Arisaka (ground mum are more prevalent, affordable, but less collectable) and Italian Carcano.  Both can be found usually for $200-250

Past that the sky is the limit if you really get into collecting.

Nice list but you have to add a M1 carbine

Mosin and RC K98. If you get the bug after that then I would suggest better options. Those are good starters.

*collect by countries or WWII powers: Japan, Germany, USA, England, etc
*collect by gun maker: Remington, Winchester, S&W, Russian (Tula or Izzy)
*collect a specific make you like: Enfield, Mosin, Mauser,
*collect by year
*collect by gun type: bolt, semi, revolver, semihandgun, flare


Have fun, buy what you like at the right price, wait if you question the buy, pounce if you know its the right buy for you, read the warnings from the dealers and expect the worst.

If you're buying on an auction site, and the seller doesn't specifically mention the bore, than assume it's a corroded mess.  A "good" bore isn't.  
If the seller says "no import mark", it may mean they didn't look very hard for it.  

If you're going to buy a Mosin Nagant, get a M39, not a 91/30.  You can thank me later.
K-31's are very accurate. Ditto 6.5mm Swedish Mausers.
As others have said, get a CMP M1.  

55_grain

If you want WWII feel with modern ammunition, look at a Ishapore 2A1.  Its like a MKIII Enfield redesigned to fire 7.62x51, although there is some debate as to whether it can handle .308.  Also, if you decide you want an Enfield 303, CTD has rather inexpensive Greek ammunition at the moment

When a specific gun is commonly available through normal distribution channels the prices are generally at one level.  Once that common availability dries up the prices will spike for a while due to all the people who freak out that they "missed" it.  Then the prices usually settle back down, but are still generally much higher than when the gun was commonly available.  Personally, I'll buy anything that I'm even remotely interested in if it's under about $400 and is available through the dealers.

To that end....   RC K98s are currently $400-$500 from multiple sources.  M1 Garands are $650-$700 from CMP.  Mosin Nagants (91/30s, M44s, Type 53s) are widely available for $125-$250.  All of these are going to go much higher when the distribution channel dries up.  Buy them now, buy two or three.  Garands for instance, they will be $1000 once CMP is sold out.  You cannot go wrong buying one from CMP now.

Don't blow you wad on Enfields, M1 carbines, 1903s, and things like that.  They are already gone from the distribution channel.  Their prices spiked and have mostly settled down.  The continue to go up slowly in value, but they won't be making any large gains.  There are thousands of them in private hands and you can get one any time you like on gunbroker or other 3rd-hand sources.  Also don't get sucked in, when K31s went out of stock at all distributors a couple years ago I saw them commonly trading at $500.  Now they have become available again and the prices are back down.  If something you want sells out, be patient.  You'll find one for the right price eventually.  I watch my local for sale boards and I've got a few guns at very good prices.  Even my local gun shop seems to have good prices on trade-in C&R guns when they get them in.  Just keep your eye out and when a deal comes along be ready to grab it.

-J

Mosins are your best bet. Maybe enfields. Anything US won't be cheap.