I know there are PLR products and some affiliates use those, though really if you want to compete with the affiliates giving away their own products you need much higher quality.
Also, have you noticed significant increases in conversions when offering bonus packages than when not? For my own somewhat small lists, I haven't. Everytime I have offered bonuses (usually ones given from JV pages), there has never been any increase in conversions and sometimes maybe even less than when I don't offer anything. So I had stopped ever trying to add bonuses. Maybe I just need the right ones or types of bonuses.