The answer depends at least partly on what part of the country you're in. In my area (northeast Florida) the best price I've found on new .45 lately was between $30 and $35 for a 100-round box of Winchester White Box (WWB). At one of the ranges where I shoot, they had 50-round bags of factory reloads for $14 and change (call it $15). That was for members only and limited to one bag per day. At another range, the members' price was $16 and change for a 50-round box of factory reloads. So, unless they sold you non-factory loads, I'd say you probably got a reasonable deal.
New ammunition is direct from an ammunition manufacturer, such as Remington or Winchester. They control the manufacture of each component (case, primer, bullet and propellant) or they buy from one source. Either way, ALL of the bullets, are the same, ALL of the brass is the same, etc.
Factory reloads use spent brass, along with new bullets, primer and propellant. Their parts will also all be the same, except for the brass. They also use quality control on par with the manufacturer's, which means you can count on the components to be uniformly fitted, etc. Popular brands in my part of the country include Georgia Arms, Atlanta Ammunition and Space Coast Bullets.
Non-factory reloads are made at smaller shops, and, of course by individuals. It's really difficult to say what you're going to get. This isn't meant to give you nightmares. I frequently shoot rounds reloaded by an individual. I've had one FTF from a round in which the bullet wasn't seated quite properly into the brass. No big deal. A double charge of powder, though, could be a big deal.
One other way of getting cheaper ammo is to buy ammo with steel cases instead of brass. This stuff is always new, as the cases can't be reloaded. Blazer (different product line than Blazer Brass) and Wolf make a lot of it. Here's a thread on what others think: http://www.firearmstalk.com/forums/f20/steel-cased-ammo-520/
Check with the range before you buy a bunch of ammo. Some ranges will only let you shoot what you buy there. Some will only allow factory new and/or factory-reloaded ammo. Some do not allow steel-cased ammo. And some (frequently those who don't allow steel cases) don't let you pick up your brass and take it home. A lot of ranges will have that info on their websites.
In most states, Wal-Mart is a great place to check for ammo. There are some states in which Wal-Mart can't sell ammo, but here in Florida, they usually have the best prices on new ammo (when they can keep it in stock).
When it comes to defensive ammo, I'd suggest you do some research, decide what you want, then shop around a little for it. Defensive ammo is usually quite a bit more expensive than target ammo, but it's made better, and you might be trusting your life to it. You'll find plenty of discussion around the web on what defensive ammo is the best.
Sorry for the dissertation. Everything above is my opinion and guaranteed to be worth every penny you paid for it.
Welcome to the wonderful world of the .45.