depends on the mod your downloading
You need mods. I would look on YouTube.
No minecraft mods don't cost any money but it sometimes may be a project to get them.
You should download the mod that you want like christmass mods or else.
There is no blood setting in minecraft. That is only found in Gore Mods.
If they are well known mods and you get them from a trusted website, then they should be ok. Always remember though to check what you download on your computer. Remember Mojang cannot offer any assistance on the modded version of the game.
All minecraft mods are free if you have to pay for it its illegal. you only need to pay for a premium account.
Mods are Minecraft 'modifications' that people have made. They can be simple things like new creatures or new tools, or they can be complex, like expanded redstone functions, new dimensions like the Aether, etc.
You have to download a mod (from modification) to do this. I've linked to a few useful mods. The last link is for help installing/downloading the mods. Note: Mods are legal, and in fact EA (The Sims' parent company) has specifically stated this. There is no illegal activity involved in downloading a mod. Also, the links are from The Sims 2. If you would like The Sims 3 tail mods, then you can search the modthesims.info website for tails and download them.
You have nothing to worry about when downloading mods from Planet Minecraft, it is safe.
Yes, as long as you don't use it with any other conflicting mods, or mods that cause the build craft mod to break.
you cant without mods