First your going to know what type of switches you would like
https://wiki.installgentoo.com/index.php/Mechanical_keyboards
^ is a pretty good guide
You more common switches are Cherry MX Blues, Reds, and Browns
Blues - Loud and heavy
Red - Light and Quiet
Browns - Something inbetween
I have blue switches and a buckling spring because I like the clacks
Also your going to want to look into what % you want
Here is a comparison between 60 and 100
https://rhino.im/u/0021/IMG_1302.JPG[/img]
Most of your $100 +/- 15 boards are "LE HAXOR GAMIN KEYBOARDS" but there are a multitude of decent ones.
My first mechanical keyboard was the CM Quickfire Storm Blues
http://www.custompcreview.com/wp-content/uploads/2012/12/cm-storm-quickfire-tk-custom-pc-review-16.jpg[/img]
pros:
Cheap
Anti twist cable
low profile
metal back board
media/function keys
cons:
keycaps a little cheap
one of my LEDs failed after 6-7 months
Build quality could be nicer (I am satisfied with it but some may be picky)
based on preference:
Number toggles between the arrow keys and the number pad
low profile
Blue LEDS that have multiple settings
Blue switches
If you want something less flashy look at this
http://www.newegg.com/Product/Product.aspx?Item=N82E16823201083
it's even on sale because of Black Friday.
Currently typing on a Unicomp Spacesaver M :^)