I think 30% conversion would be a good rate if you have a very targeted list.

its very difficult to make 30% conversion rate....

It really depends on a lot of variables, mostly the relationship you have with your list and how targeted the offer is regarding what your subscribers signed up for initially.

So yeah you can get a 30% conversion rate, but also a 0% conversion rate so that's a hard question to answer without some more (basic) info.

30%? That's pretty high. I'd imagine that number being much lower (less than 10%). But I guess it also depends on how targeted your list is...

Good luck.