Got started by completing over 70 freebie offers (email/zip submits) back then, I could spend 1 hour, $40 on trials, and profit $1k+ (My largest take was 8k, and I spent $200 bucks.) I made over 50k doing that, eventually I found out I could make money promoting them... and that led to everything else. Would have been a lot more money if one company didn't fold.
Nowadays, completing those freebies for profit is impossible and half of them just try to screw you.