Personally for freerolss i like Redstar (bout 7 bucks if u win) made a couple of dollars and since put it into smal buyins and so far made a bankroll over 50 bucks. i also like the freerolls at stars, esp the razz and stud games so i can learn, and if u are good enuf to outlast 3000-5000 peeps, ultimate bet has a funk load of freerolls (just u can be really bothered by people at this site as i have had a few people givin me sh#t and ive moved and they've followed me and still keep goin)
Stars. Their HORSE, O8, and Stud8 freerolls are immense fun. Usually fields of 6000+, I can usually get through the first 5500 just playing solid, but the best players usually remain so it gets hard to cash. If you're after HORSE freerolls, other than Stars, Full Tilt runs one every night at about 10.30pm GMT (I think thats half six in the evening eastern time).
bodog has 3 daily $500 guaranteed freerolls.. first place pays $120, 63 overall payed places. those 3 tourneys are the best you'll find.. ultimatebet and absolute poker both have freerolls every hour, nothing huge though. ultimatebet has a $500 bonus dollars, but even if you win in there, you then have to earn a certain amount of "bonus points" to release the dollars.
i'm a freeroll player and those are my 3 favorite sites to play.. I also play a ton on WPT's site, although you pay $20 a month.
CARBON POKER has lots of freerolls with big purses. Daily $1000, weekly $10,000 and monthly $50,000. But you do have to qualify for these by playing cash games. But they also have several $50 freerolls daily, plus a series for new players.
But the best freerolls and add-on tourneys are right here at Cardschat. The value in some of those is amazing.
The merge network, of which carbon is one. as the above poster said, huge daily freerolls that are easy to qualify for. I play three ring games at a time for an hour daily and it satisfies the requirements. I play mine on pokercs. Reefer opted out of the daily ones, so I switched to cs. All part of Merge.