Seal N Send Invitations Invitations?

Invitations? - seal n send invitations

I am currently testing this new invitations and seating is a joint venture between the N Send Invitations (which are much simpler), and regular invitations.
If I decide to call regularly, what should I buy? You have all these things on the list with the invitations that come with it.
Examples: Invitation outer envelope w / return address printed on the invitation, invitation-lined inner envelope, the receipt of the file, respond and react note on the map of the informal. What does all this mean and what should I buy?
These are not my invitation, but a link attached, so you can see what I mean with the tender and also a link for the seal s invitations.
http://www.annsbridalbargains.com/We_Vie ...
http://www.annsbridalbargains.com/CasPag ...
Help!