yellow letters and list source

[Duriel Taylor]

Hello Everyone, 

As I prepare to use yellowletters.com and listsource.com, I have formulated a question that I can not find an answer to. Ok so these mailing marketing services (yellowletters) do they provide me with "motivated sellers", to mail to directly? In their questionnaire, they ask me for my desired/potential receivers; divorcees, absentees owners, etc. If they provide the individuals and send them the post card or yellow letter directly, why would I need to use listsource? From what I understand, listsource provides me with potential names and or addresses of people whom I could contact directly then I would have to send them the marketing material(s). Also is the postage prices/cost included in the price of the yellowpages? For instance, its $150 per month at listsource.com; $.20 per lead, which comes with 750 leads per month. But they do not mention the envelope nor the stamps cost. The way I figured out per monthly with listsource.com is listed below. 

$150 (750 leads) + $.41(750 stamps)= $307.50 + $59.50 (2000 each envelopes for $59.50)= $517 per month. 

Could someone give me their feedback to ensure I am analyzing my month expenses correctly? I look forward to hearing everyone's feedback. Thank you all in advance. Take care.