You'd need to specify what do you want to target, what is your product.
The list vs the offer need to be compatible
For example most of our databases were from our own and third party dating sites, verified users - male 35 + demographics
Various GEO's from country specific sites.
Mailing is quite complex these days and the setup and work one needs to put into successful delivery will reflect in the pricing.
If you talk about visits to a landing page - that is CPC (cost per click)
You can check with some traffic brokers that offer email traffic on a CPC basis for a ballpark figure.
Then again, targeting the right mailing list will be key for the actual conversion.