My father used to have a combination single shot 22LR and 12ga rifle.  I have been thinking about getting one.  I am finding it difficult to locate one.  Not even sure what they are called.  I would like it for general small game gatering.  I would also like to have it in 22 lr & 12 ga.  I have 22's and 12's.  Don't want to add another caliber to the prep list.  Any recommendations and ideas on price range?

my brother has one in 22lr/410, it's a savage/stevens, I think he paid approx 3bills for it new 15 years back or so.

Go to Gunbroker.com and search for Spartan or Savage over\unders...you'll find plenty!

These are called Combination Guns.

http://en.wikipedia.org/wiki/Combination_gun

Your father may have had a Savage 24v.  Discontinued for a while, they had a very heavy trigger pull.  
Remington Spartan 94 may be what you are looking for.  That is a current production combination gun, available in an assortment of caliber combinations.

The Savage/Stevens M24 is great. The only drawbacks are availability and weight. They're scarce and heavy.
The Remington Spartans were previously sold under the Baikal name and are purported to be a good value.
The Springfield M6 Scout is a neat package, but it's no longer in production and now commands ridiculous prices.
I like over-unders more, but an effective Plan B may be one of the Rossi combos with the interchangeable barrels.

One of the original models was the Savage 24C Camp Gun, but I think it was .22 over .410. That was the "takedown" model which came in a little cloth carrier.

I have a24C 22LR-20guage. The c models are short (20"), with no choke. Thinking about getting the local smith to put mod. choke tube in it.

There are three general options I can think of.

1) Early Stevens/Savage.  At one time stevens and later savage made a number of small-frame over/under combo guns.  These were first available in .22/.410 (I own one) and later a variety of calibers and gauges (.22/20, .22 WMR/20, etc).  Savage named these the Model 24, with various models (ex: 24C).  These were not a bad compromise.  They worked relatively well, and I love em for squirrels (Use rifle when you can, shotgun for tree tops in situations whe you are concerned about were the bullet comes down).

2) later Savages in .223, 30-30, etc over 20 and 12.  These later guns were chambered for substantially larger rounds.  Teh guns themselves are also quite large, relatively cumbersome and kinda clunky.  They are not cheap, and wieght is a big issue.  Personal option:  You can do better by buying a simple H&R in 30-30, .223, etc and then adding a shotgun barrel for $90, or buying a package gun with two barrels outright.

3) Various imports.  Valmet once made a series of these in centerfire over 12.  There are a few other isolated similar models. In general you either end up spending $1500++ or end up spending $400 for a brazilian/russian cheapo.

EDIT:  4) Springfield folding 22/410 or .22 hornet/410. Scarce and $$.  Neat if you can find one.  Dsicontinued/

The early stevens savage small frame rimfire over 410 or 20 are valid and useful.  The others are too damned cumbersome and heavy to be worthwhile.

Fro.

I have had a number of these over the years and Mel Tappan recommended theSav24 in 22lr/20g as a GP survival car gun; he suggested adding a converter to allow the use of 45acp out of the 20g barrel. Wtih the 45acp (or 44sp or whatever) 6" converter tube, 20g clugs, 20g shot, and 22lr one could take everything from grouse to deer with the same gun.

Having said that I would not recommend one as it is not a very good 22, not a very good 20g, and not any better than a 4" big bore pistol with the 45/44 converter tube. the 2.5lb chipmonk 22lr with a good post front sight, read peep and good trigger is a much better 22lr. Any being a fairly good pistol shot, I can hit just about as well with a 1911 or glock 35 out to the limits of the round.

Another alternative would be a new england single shot with a 12g and 22lr or 308 tube. you could use 32acp/308 converters or light loads in the 308 tube for small game. It would take a while to switch from shotgun to rifle, but I think you would end up with much better examples of those two firearms. Or a contender carbine with say a 16" 45colt/410 tube and perhaps a 22lr 16" barrel.

My only combo o/u is a Springfield M6 scout (.22LR/.410).  I have it dialed in (irons and a Reflex sight) for the .22LR.  The .410 is okay for 20-30 yards...that's pretty much the limits of those little shot shells in my gun.  Slugs pattern like crap, so this is definitely not a viable slug gun (about equivalent to a small .38 special load I think).  I will say that the 5-pellet buck shot loads are good for close range defense/hunting and I can keep all 5 pellets on a full-size man silhouette at 10-15 yards...again, about the max limit.

The problem with most combo guns is their point-of-aim for both barrels and the single set of sights.  If you scoped the rifled barrel with see-thru rings to zero the shotgun barrel with the irons, you might be okay.  However, the price for most combo's are getting up there...and I don't think Savage is making their model 24 anymore.  For the money, I honestly think a simple H&R single shot 20/12 gauge and a decent .22LR pistol (Single Six, Mk II/III or Buckmark) would be a great combo without sacrificing the need to swap barrels (which is another option and both Rossi and H&R have good choices...); the weight would probably be about the same as well.  With the larger 20/12ga, you could definitely take game as large as deer and all fowl and small game on down...

Check on Gunbroker for Savage (model 24) or the older Stevens.  They are pretty expensive, so it may not be a cost-effective choice

ROCK6

As a kid I had a savage 24 .22/20 ga., was a good gun and shot a lot of game with it.  With a scope on it was a pretty accurate .22 and shot slugs well too. Still not as good as a dedicated .22 or shotgun andIi traded it off. In a one gun survival situation I can certainly see it's advantage. I would like to get one of the short "Camper" models that stored in a case.
I know Savage made these combination guns in larger calibers such as .222 and 30 30 but don't know about 12 ga....maybe the new ones?
A friend of mine has a combination 12/ .222 made by Tikka...he loves it and uses it for Turkey hunting. Very accurate rifle he says...imagine you could get an addapter that let you shoot .22LR out of the rifle barrel.
Years ago I had a drilling made by the company that made LC Smith [Hunter Arms Co.]... side by side 12 ga. with a 44-40 rifle.....pretty neat and wish I still had it.....T.

My first gun ever was a Savage. 22/410 Dad bought for me in 1968 (yeah,I'm old) I still have it and it still works fine after a lot of use and abuse over the years. I recently bought the .22 mag./20 gauge version on Gunbroker for around 300 bucks in excellent shape for a truck gun. I think they are a very viable foraging gun and both mine are plenty accurate enough for hunting.