I'm new to Bitcoin mining so I just wanted to know if you could convert altcoins to bitcoins, and maybe a few starting mining options? I assume that a lot of altcoins make a few bitcoins.
You can get an idea of the value of each altcoin at Coinmarketcap.com
I use Poloniex, as others have mentioned. Another exchange is bittrex.com - please note that no exchange handles 100% of altcoins. There are just too many, and unfortunately there is quite a bit of corruption involved in the process by which altcoins are added (or dropped) by exchanges (kickbacks/bribes, etc.). Generally the announcement thread here on bitcointalk for each altcoin will list the exchanges each altcoin trades on.