I bought a hammer drill once from a traveling tool sale thing (I dont think it was harbor freight but very similar prices).
They come to town about twice a year and set up in the National Guard Armory.
Very cheap prices.
I think I paid 10 bucks for the 1/2" drive hammer drill. I needed to drill about 20 holes in a concrete pad for anchor bolts, so I figured it would last that long, surely.
But, as always, I was wrong.
On the first hole, I got about half the needed depth and the drill started making a funny noise, then pieces of plastic starting flying out of the air vents around the brushes. Then the thing locked up and got pretty hot before i could release the trigger. After it cooled down, it went straight to the trash can.
I wound up borrowing a friends Milwaukee drill (which by the way are excellent hammer drills).
So I shy away from buying ANY cheap tools, especially ones expected to do serious work. (Such as a high speed slot cutters and other router bits).