What internet speed do you need for online gaming

usually 100mbps is the recommended for an online game.

I'm going to go ahead and say it depends on your game. 100mbps is certainly incorrect, unless that was supposed to be the speed of your network card. A T3 line, which is $6000 to $12000 per month, can hit 45mbps

For a game such as World of Warcraft, I played that over uncompressed dial-up.
A game such as FFXIV which requires a lot of downloaded information you may need a 10mbps connection for it to be very fast, but it would most likely run well on a 1.5mbps DSL link.