A customer can buy a product at special price. If the customer wants to buy the same product again, it will be at normal price instead of special price. That means, that a customer can only buy a product at special price once a month.
I have an idea that you can use Catalog Price Rules / Shopping Cart Price Rules, but I really like an example on this or a link to a ressource to use.
You can do this through a shopping Cart Price rule, if you create one rule per month.
In the rule information, set : Uses per Customer to 1.
Therefore he can benefit from the promotion only once.
Okay, but the rule are for all products, with different prices. So I would have to create a catalog price rule every month, for all of my products. I'snt there a module or anything to make it easier ?
Other way around, is to create a customer segment per month : customer who didnt place an order.
Then all the customers from this segment are eligible to the promo rule that gives discounted price on whole catalog.
Once they place an order, they are no longer member of the segment and will pay full price.