Personally I tend to prefer the .45 Colt and .44-40 cartriges. Mainly because they are more "period approperiate", lend themselves to using black powder quite well and still have a bit of thump to them on the other end. While Ruger Vaquaros and Blackhawks are pretty popular, I refuse to buy Ruger guns due to Bill Ruger's pro-gun control politics. With the Rugers out of the question I went with some of the Italian imports and have no problems with them at all. To date I have one Cimmeron .45 Colt, an EMF Hartford in .44-40 and one of EMF's 1875 Remington revolvers in .45 Colt. All of them are top-notch guns and not all that expensive either. Recently my re-enactment group was looking into getting a revolver to raffle off for a fund raiser and here's some of the guns we came up with and what the dealer price is on them:
EMF Hartford model (1873 Colt clone): In .45 Colt, .44-40, .357 Magnum, .38-40, .32-30 and .44 Special with either 4 3/4, 5 1/2, or 7 1/2 barrel will cost you $279.90
EMF Dakota model (1873 Colt clone): In .45 Colt, .44-40 or .357 magnum in the 4 3/4, 5 1/2 and 7 1/2 in barrel lengths are going for $235.00
EMF 1875 Remington: Comes in .45 Colt, .44-40 and .357 magnum with either 5 1/2 or 7 1/2 inch barrels are going for $319.00
EMF 1875 S&W Schofield: Probably a little more than you are wanting to pay but their break-open design makes for very fast reloading. They come with the 5 1/2 inch barreled Wells Fargo model or the longer 7 1/2 inch barreled cavalry model. These only come in .45 Colt though. Going price on these are $525.00
Cimmeron 1873 Custer cavalry model (Colt clone): These are the same 1873 Colt revolvers that EMF has but they come in a much more beautiful (though not as durable) charcoal blue finish on an old-model frame. Their big deal is that they have the correct markings for Custer's 7th Cavalry companies and only come in .45 Colt with a 7 1/2 inch barrel which is also correct for a cavalry model revolver. The going price on these are $349.00
Cimmeron 1872 Open-top: This is the predicessor to the 1873 Colt revolver that sort of bridges the gap between the cap-n-ball age and the newer Colts that came out the next year. They have the open top of the cap and ball revolvers but have a cylinder that can take metalic cartrige ammunition. Barrel lengths can be had in 5 1/2 or 7 1/2 inches. Ammo listings for this revolver are .44 Colt, .44 Russian, .45 Schofield, .38 Colt and .38 Special. Keep in mind though that you have to use low pressure rounds or black powder with these guns though due to their more fragile (though very eligant) design. Going price on these are $369.00 This by the way was the gun my cavalry re-enactment group went with in the .44 Colt/.44 Russian chambering.
As far as rifles go, you might want to check out one of the Rossi rifles or one of EMF's Hartford 1892 rifles if you are on a budget. I have one of Cimmeron's 1873 Winchesters in .45 Colt and another Cabela's Uberti 1866 rifle in .44-40 that are my favorites. Problem with those two rifles are that they are not cheap.
Rossi makes a good gun and I have had one of their carbines for a few years. EMF is now importing a clone of the 1892 Winchester as well that is carrying a decent price to it as well.
As far as the 1866 Winchester clones from Uberti go, these are the brass framed Winchester rifles and can be had in .45 Colt, .44-40, .38 special, .38-40 and .44 Special. The carbines with their 20" barrels are going for $579 and the rifles with their 24" barrels are $20 more for $599.
The 1873 Winchester clones from Cimmeron are a little stronger with their steel frames and the side plates that are easy to remove make cleaning up after black powder the easiest ones to clean. Their calibers come in .45 Colt, .44-40, .357 Magnum, .38 Special, .44 Special, .38-40, and .32-20. Here you can get extra long barrels but the two most common lengths, the 20" carbine and the 24" rifle, cost $679 for the carbines and $719 for the rifles. They also have the short rifle that looks similar to the full size rifle but with the barrel cut back to the carbine's 20" length going for the same price as the full size rifle of $719.
The EMF 1892 Hartford models are clones of the Winchester 1892 rifle. It appears they only come in .45 Colt and can be had with either the 24 inch rifle barrel or the 20 inch carbine barrel. The prices on these rifles are pretty cheap and would probably make a VERY good entry level rifle into the sport. Here dealer prices are listed as $366.90 for the rifles and $267.90 for the carbines.