Chevy454,
I am also working on a subscription based project. It is a little different than yours but, I have been doing my homework on this concept.
You should be able to do this right now with no hacks and very cheaply using Josh's myPaymentPal. First understand how it works. While it has a lot of features, at the core what it does is it will add a member to a specific group for a specific amount of time. So here's da plan...
1. Set up a forum, or multiple forums that will hold the classified ads.
2. Give "Read" privledges to these forums to the non-paying group. I would include "Guests" and "Users" (the group most visitors are assigned after basic registration) They will then be able to read the classified ads, but not post to them.
3. You then set up a group that has "Read & Write" privlidges to any classifed ad forums . So when a member is belongs of this group, they will be able to post to these forums.
4. You use myPaymentPal to sell subscriptions to the classified ad group. You could actually have multiple choices. Such as 1 day for $XX / 10 days for $XX / 1 month for $XX / 1 Year for $XX / etc
5. In summary... A member of your site would be given the option to purchase posting rights to the classified ads section for a set amount of time. He could choose from several plans. the longer he can post, the more it would cost.
This plan will not give you the pay per post ability, but that sounds like a bear to do, coding wise...
In my humble opinion, that might be an overkill. I think the trick here is to set a pay structure up that is fair to a serious visitor, yet will run off a cheapskate. You might have a few that will buy the cheapest posting package (least amount of posting time) and post a ton of ads, but I bet most of the members that plan to post a lot will buy more expensive plans so they can plst at their liesure and not be rushed.
Anyway you can start there and see how it works. If the system gets abused by a lot of people buying small access plans and posted gazillions of ads, you can look into custom coding then. It would really suprise me if this happens. In my experiences in life, anything that costs anything tends to run off cheapskates...
Good Luck...
