Nothing wrong with 50/50, but you pay a bit more for it than you would if you bought straight antifreeze and distilled water and mixed your own. Many automakers have their own blend of AF, which I believe is somewhat legit but also serves to pad their bottom lines. They are usually color-coded: old school ethylene glycol blend is fluorescent green, I believe some GM and foreign makes use a red or purple colored type, and my '08 Mustang specifies a gold (yellow) colored Motorcraft or equivalent. Green Prestone or equivalent, labeled 'Suitable for All Engine Types' is appropriate for our iron lumps. It's not advisable to go against manufacturers recommendations and certainly not to mix types; I've heard of coolant gelling when some types are mixed. Some AF blends, specifically those for sale in Canada, require a bittering agent to repel animals, like dogs, who otherwise will lap up a coolant spill like it's melted ice cream, and die a painful death.
Last I checked, the green stuff--Prestone, Xerex, or other--can be had for about $11/gal on sale, and a gallon of distilled water costs about $1. That's $6 give-or-take for one gallon of a 50/50 coolant mix; the premix appears to run a couple bucks more (but the convenience may be worth it). My BJ8 specs 2.5gal (US) for a 'dry' fill, but I've never gotten more than a gallon and a quart or so. I dump a gallon of AF in, then add distilled water until it's about 2" below the bottom of the radiator filler neck; any more than that goes out the overflow pipe.