Because I am nice and all, I have figured out what an endgame goal would be for ourselves.
Zombie Plan A
Stage 1
Infection, whether by bite, spore, or implantation, this is where any human starts. We as an organism start appearing at this point, with us fighting the immune system over control. We would gain control at this point, but nothing special yet.
Stage 2
False recovery. Yes, they seem better, and it doesn't seem like anything has changed. Even though it may appear to be better, any infected will seem "slow", but still sane. They will probably take it as part of the recovery, and ignore it. During this time, the parasite is rewriting the brain for our uses. This is the last possible stage for treatment. The subject will advance from this to the next stage in about 48-72 hours.
Stage 3
Zombies. The person's brain has been rewrited, for our purposes. The core instinct is to get in large groups of people, but NOT to act agressive. Spore sacs are appearing on them, but they are so small that it looks like a bumb on the skin. Contact with these bumbs would release a small amount of spores, but not a lot due to the spore sac not developing yet. These indivduals would be 72 hours to 5 days after the initial infection.
Stage 4
ACTUAL zombies. The individual will, at this stage, start showing agression towards other humans. Due to our individual nutrient gathering, we have sharpened the bone with our absorbtion of its minerals. These would actively attack groups of humans in large groups. Spore sacs will trulely start emerging at this point. Rupturing these sacs would truly "explode" in spores, infecting all people in a small area. This stage runs for about 2 weeks after entrance into this stage.
Stage 5
SPORE zombies. The subject in our mind will attempt to go as high as possible. Why? Spore sacs will begin covering the body, to the point of beginning to degrade our inevitible super senses. When the zombie reachs the point of its destination, it releases its spores from its sacs, becoming an ordinary Stage 4 and releasing spores up to miles away. Evey week thereafter the zombie will return to this stage for a total of 3 times.
Stage 6
WEAK zombies. Our parasitic absorbtion finally has become apparent, and these individuals now exist. Unlike stage 4 zombies, their bones are almost gone. They still feed the parasite and emit spores, but the human which makes up the host is actually dead at this point.
Stage 7
Our Parasites Adult form. For the time previous to this, these monsters had enjoyed the nutrients our body has, while asexually emitting spores. After our annialation of the hosts body, around 1-4 individuals this level should have emmerged (with the hundreds of others dying in stage 1 and 2, and there might be SOME not fully developed ones inside as well)(it is also to note that large individuals could support more adults. An elephant could probably support around 15). These individuals are fast, mobile, and relatively small. The first thing they will do is mate, and both sexes take some of the eggs. These spider-like indivduals will be keen on infected individuals and rush to infect all non-infected. The attack consists of hit and run, with jumping on the individual and injecting a few eggs (remember, our spores are assexual, our eggs are sexual) into the system of the host. They will then ignore them due to pheremones being emmitted from our spores saying "don't shoot!". The adult will then seek someone else, and the cycle continues for about a year or 2, in which the final stage appears.
Stage 8
End of our Parasite's life. All remaining energy will be used in the production of spores. These guys resemble Stage 6 zombies in behavior, and are terribly sluggish. After about a month or 2, these guys die.
Please note that we infect all species, but plants infected would be spore generators instead of zombies. The tree would still produce nutrients for itself, making "Spore Trees' last for quite a long time.
Now how much would THAT cost?