Party Poker was the easiest for me and one of my regular sites.
Their bonuses require 7x play. All you need to do is participate in a hand (even if you fold without having money in the pot) and if the pot is raked, then it is counted as a Raked Hand (RH) for you.
For example, their monthly reload bonus is 20%. If you deposit $100, they will put $20 in your "Pending" account. You will need 7x20 = 140 RHs and Party will move $20 from the Pending into your cash account. On the Limit tables, you can usually play about 40 RHs per hour and collect the Bonus in about an evening. It's also easy to view the RHs.
Iceberg