Im new to upgrading pcs and pc gaming in general. I bought a best buy computer and now that I'm more interested in gaming have done some upgrades to it. My question is my pc has a single stick of 8gb ram I bought a kingston dual channel kit to replace it. Can I run the 2 sticks in dual channel and then throw the single 8gb stick in the other color slot or will it mess everything up? 

Well 8GB is plenty for gaming. You can through in the kit and it will work but it won't operate in dual channel mode anymore. But you won't notice the performance difference. 

So I'm better off having 8gb of dual channel ram than 16gb of total ram with the slow single stick in there

RAM sticks aren't by themselves "Single Channel or Dual Channel." Any RAM stick run one it will be single. Two with matched colors dual channel. 

No. You won't see a difference between single and dual channel however I'd rather have more RAM. 

+1 ram good