Look for sites that pool rewards and pay via through coinbox and microwallet, as the longer wait for a one at a time payout is restrictive.
A google search will provide all the info you need to start. The folks who have "whole BTC' in their wallet tend to comment that it is "not worth it" to go through the motions of collecting free BTC, but today I was paid out by three sites, and I now posses BTC (value:$1.00). One site pays "well" for visiting other web sites, again, a google search will find this for you.
To close: Yes, you can get free BTC, no, you won't get a lot for the effort. I still click on the three forms I noted above, but have abandoned the "single payout" sites.