As far as copyright, I'm sure the vast majority of people on BB have never copy written their photos, I never have. I believe that you can copyright more than one photo at a time and do a batch of them, so that $35 cost doesn't end up "per" photo.
Yes, you can register many photos per $35 registration fee. I register all of my photos now because it is very affordable insurance in case of infringement. I've even been through a lawsuit process that took 9 months before it was ultimately settled. That was a learning process.
If you don't have a valid and timely registration, you don't get to sue. No matter what anyone has told you about your copyright being valid the moment you click the shutter, it doesn't matter when you go to Federal court (copyright is federal law, so it's federal court). The judge will insist upon verification of the copyright registration and note that it was in place before the infringement occurred, not after. So if you don't have that, you don't have any leg to stand upon.
Providing you have a valid and timely registration, you can find attorneys who will represent you on a contingency basis. That means they won't charge you for their labor, but will take a percentage of any court winnings or settlements (perhaps up to a third). It does not mean you aren't liable for any other expenses, though. There are court filing fees and other costs that the attorney will not bear for you.
There is no such thing as a contingency defense. Paying for attorneys is expensive and its one of the reasons why most copyright infringement suits are settled. That's cheaper than fighting it and still potentially losing with a much larger award of damages. Besides, the law favors a settlement. The courts cannot possibly try all of the cases filed. They may only find 2-3% that go to trial.
Attorneys who represent you on a contingency basis are not really doing it for you. They don't care about your anger, frustration or any emotions at all. They are using you as a means to make money. Technically, they are representing you and must do so in good faith. Realistically, they will stonewall and put up roadblocks if you want to pursue an action they don't believe is profitable for them. Be wary of your own attorney's motives.
Finally, decide if making a lawsuit is really the best course of action. If some random blogger uses your image, big deal. I found one of my images used without permission by an AOL travel blog called Gadling. Should I sue AOL? I'm debating it. The truth is that filing a lawsuit is a pain in the ***, even if you win.