How often can you sign up for a company?

I have made $5000 in a year and a half of 'online offers'. So needless to say, I've signed up with A LOT of companies. My problem now is that the offers I want to do are posting many companies that I've already done in the past. I've tried signing up for some companies twice (with different e-mails), but some companies will not let me due to my address being in the system and possible IP address.(?) Am I just stuck for now and wait until more companies are added to online offers?

Does anyone else have this problem?