Personally, I suggest Cherry MX switches keyboards. They are reliable and easier to play with keycaps later.
Under 100 bucks.. hmmm... Ducky is good, but get the PBT edition. I dunno how much Ducky kb is. sorry.
Noppoo Choc mini is good too imo. You can buy this from ebay.
Razer Black Widow is ok. But i don't suggest to get the Ultimate(LED version). It has so many problems.
The normal non-LED one should be ok.