Also what do you mean there by: "a two year membership payment makes a good change to get the whole year for free"?

I don't mean that you should have changed the "change" with "chance" (a thing that you should do) i mean the following question:

There is not any 2 year membership available as i see! Only for ½ year or 1 year!
If you mean buying 2 one year memberships at the same time, then i have another strategy:

1)Buying 2 one year memberships at the same time:
Current COST = 2·28 = 56 €
New COST = 2·30 = 60 €
Probability of getting 1 year for free = 50 %
Probability of getting AT LEAST 6 months for free = 50 %
Probability of getting EXACTLY 6 months for free = 0 %


2)Buying 1 one year membership now and the other day another one:
Current COST = 2·28 = 56 €
New COST = 2·30 = 60 €
Probability of getting AT LEAST 6 months for free = 75%
Probability of getting 1 year for free = 25%
Probability of getting EXACTLY 6 months for free = 50%


So what we have is that buying with the second method 2 years, you get 75% of having at least 6 months for free or even 25% for 1 year for free. While with "your" proposed way we have 50% for 1 year for free but if we don't suceed we get nothing more....

I would choose my proposed way as i prefer better chances than better prizes, if actually you will allow the BONUS to be valid this way....According to the aforementioned rules for the bonus, my way is 100% legal.....