In my opinion,  there are 3 types of music bootlegs out there.

1. The First being the obvious one. These are usually Live or unreleased Demo recordings. The cd's / records / tapes / dvd and vhf 's usually have weird record company labels on the, or none at all. Sometimes the recording quality is very poor. Usually most people who buy these know they are bootlegs but just want the songs. When buying these items, you have to really watch what you're buying. You could buy the same songs twice because the covers change constantly. 
   


2. The second type is the bootleg copy of a well known release. This is an item that is in high demand for collectors. These are very hard to identify especially if you don't have an original to compare it to. The main problem with these is they are usually highly expensive for a fake copy! Made to trick the consumer.
   
   
3. The third type is a copy of what someone claims is an official release of a limited edition item, but you never heard of it before. So seeing this you think it is real, just something you never saw before. But it probobly don't have any special rare songs on it or anything, just different packaging, also made to trick the consumer.