Have had a herd of 33 alpacas + 3 llamas for 11 years now and my father's a vet......
 
My biggest recommendation would be to learn as much as you can first, as they are much more complicated to keep than people trying to sell them will ever have you believe.  The husbandry is very different than other livestock and there are not too many good vets with alpaca knowledge around-- in addition to the fact that no meds are made for apacas; everything we use is off-label and since they've not been around in North America for that long, there's still lots to learn about these wonderful creatures. 
 
There are many alpaca websites where we all share knowledge.........Alpacanation, PacaThis on FB, Alpacastreet, Openherd are all good places to start.  The alpaca field manual by Dr. Norm Evans is invaluable, but even better is finding yourself a good mentor.  Work with someone helping them on their farm a while--this may not be what you think, after all.
 
Alpacas have been promoted as the "huggable" investment, but the truth is that few of them are actually huggable.  They are soft and gentle for the most part, each one is absolutely an individual with personality--but they do NOT like to feel confined!  In the wild, they are prey animals (NOT NOT NOT guards!) and their defense is to run.  We humans all have the natural inclination to reach out to pet their heads--where they usually least want to be touched!  There are, of course, exceptions....but I'm trying to give you an "in general" idea.  
 
Most of us won't use electric fencing; too many animals have died in it.  The preferred fencing is usually nice, expensive no-climb horse fencing--as tall as we can do it (HeritageGoose13 is correct--they are predator bait)!   Even with good fencing, most of us also have some other form of protection, whether is be proven guard llamas, livestock guardian dogs, sometimes donkeys, etc.  Locked in a barn at night presents its own problems, and isn't necessarily all that safe.  I personally know some folks who had 9 alpacas torn apart when two Mastiffs pulled a board off the barn wall and got in during the night.  Yes, dogs tend to be the greatest danger.
 
Anyway, I could go on forever because there is so much to this, and I'm probably shooting myself in the foot to sound like this--it sure won't help me find good homes for my guys (because we really need to retire from this but my animals don't go anywhere if I'm not totally convinced of their future health and happiness)......
 
Hopefully this will make you stop and think before jumping into something that you might not want to deal with later and before more animals are in need of adoption down the road.
Thanks for thinking about it!
 
josebeth1
Crias del Cielo Alpaca Farm
Hudson, OH