I have a 2008 Ford Focus that won't start. It clicks when I turn the ignition but work crank. Got any advice?

Also the radio will flicker on and off if I try to turn it on. Car ran fine 2 days ago. Also just put in a new battery.

Alternator or starter motor?

Start by checking the battery. Even if it was new 2 days ago, a parasitic drain, or a bad alternator could easily put you in the position of having a dead battery again. Also check the leads to the starter, the ground connection, and the battery leads as well. A simple loose wire can cause enough of a voltage drop that the starter might not get enough juice to work properly. Based on your comment about how the radio flickers as well, I'm thinking your battery is almost dead again, and thus, you may need to have the alternator circuits checked. If you are in the US, most large name auto part stores (AutoZone, O'Rileys, Advance, etc) offer free battery and alternator checking if you can get the battery or alternator to that store.

The clicking sound usually indicates there's not enough amps in the battery. There may be enough for the radio to work but not the starter. If the battery is more than 3 years old it may need replacing.