My alpacas have just cost me £17 to shear, trim feet , trim teeth, blue tongue, worm apply pour on etc. each which is only done once a year.
They are more of a livestyle animal, if you want them good, as they will protect lambs and can be extremely nice to have around as they are very nosey.
I agree that lambs can be brought in at night, but I keep mine in anyway for the first week of their life when they are most prone to fox attack.
As to TB, that's anyones guess if an animal is going to get that.
As to the price, shop around as castrated males are of course cheaper than anything else, if you want some go for it. I did and have never regretted it. I am just going to take on another one on loan to help someone out.