Can I buy a mobile for $100?

If you sign up for a plan or renew a plan when you buy the phone you can get a pretty good phone for a hundred dollars cause they break you a good deal. But if you already have a plan you can't get much for under 100 except the prepaid phones

it's going to be colored, that's for sure... as to features, well, u don't really expect that to have too much of those...

Of course you can and you can get quite good mobile phone for this money. For example used V3 (I can't paste link but I found one on ebay with buy it now 89$)