I've got a cheap grinder story.
I worked at an ACE Hardware for 2.5 years and they sold JMKT tools. Little stuff (screwdrivers, drill bits) in a bin for 1.99, 3.99 etc. Well, we got in about 20 4" angle grinders from them. $12.99 a piece. I thought...to good to be true, so I tested it. I grabbed one off of the shelf and went over to the small engines shop. I open the box, and sitting in there with the angle grinder is a package with spare carbon brushes. This just screams...I'm a piece of junk. So, I put on the disc and plug it in. I hit the trigger and it starts going. Decent sound, little to no vibration....for the first two seconds. Then, it starts popping (like gun shot loud) So, I shut it of and unplug it (not wanting to kill myself). When I go to take the disc off, the shaft that it's mounted to has over 1/2" of side-to-side play in it. So, instead of boxing it back up, it went right into the trash.
Moral of the story...if it sounds to good to be true, it is.