Hopefully I can help out here. Being that I am a U.S. player I can't really give you much information on sites like PokerStars
, Full Tilt, or any of the other non-U.S. accepting sites. However, I can give you some information regarding Carbon, Black Chip, and Bovada
To start, Carbon has 5 freerolls each day...but the playing field is usually pretty huge. Usually something like 2500 players each time. I am on the East Coast, so the times for these freerolls are 1:00 AM, 7:00 AM, 1:00 PM, 7:00 PM, and 9:00 PM with the 1:00 PM being a HORSE tournament and the 7:00 PM being Omaha. The others are NL. Each of these freerolls has a $50.00 prize pool.
Black Chip only has 3 freerolls daily, but they also have a $250 new depositor's freeroll as well. I cannot really remember what the prize pool is for the 3 daily ones, but I know one of them is Omaha and the other 2 are holdem. I also think that one of the holdem ones is limit though. If I remember correctly only the top 10 are paid, and I think the prize pool is something like $25 or maybe $50.
Bovada is pretty interesting. They don't really have much going in the way of freerolls that you can just join in on, but rather you need to buy a ticket to these tournaments with the poker points that you earn by playing poker at their site. However, as a new depositor bonus, you get these tickets into a qualifying satellite to their weekly $100,000 guaranteed tournament, which is pretty nice.
Honestly though, when it comes right down to it, the best advice I can give you is to become an active member here. CardsChat has weekly freerolls on all the sites that I mentioned above and more. There is another site that I use as well called PokerOwned if you feel like doing a bit of grinding to earn the points for their freerolls, but I may actually stop on their site. Reason being the freeroll prize values are very small.
Hope this helps