EMF has a fairly large line and not overly pricey:
I don't think they're the cheapest, but I've handled a few (haven't bought one yet) and like what you get for the money from Cimarron:
Those will get you started for cartridge. For BP you could try the following:
pricier than some but great customer service
great BP selection
again a bit pricier but WORTH the money for the service
And finally for BP check out Cabela's, www.cabelas.com
, bar-none the lowest BP prices. Most of their guns are Pietta, not Uberti (generally ranked no.2 and no.1, repectively) but the quality is still very good and their service is decent, too.