I offer web services such as hosting.
In a <select> field, wich option should be pre-selected? 1 month (without discount), or 12 months (50% off)?
The question might seem kinda obvious, the 12 months should be better - but what if the buyer don't want a whole year with the product, and feel bad for paying it's full price, knowing it could be cheaper, and end up giving up on the purchase?
What do you guys think?
The select field on your screenshot might not be the best solution for selecting the payment period. As a user I don't get a good experience in comparing the alternatives and probably I won't notice that there's an alternative to the very prominent designed orange 49.90/month offer. The problem here is that 50$ per month is a lot if the user wants to use your web service for a year (he can get it for half of the price) and there's no hint that the price/month will decrease when he selects a longer period.
Whenever you already preselect an option the user doesn't have to think about what to choose and he simply won't get informed that there's an alternative to select when clicking on the "Buy now" button.
Let's have a look at the Dropbox plan selection. This solution gives the user the chance to easily notice and compare every payment option and the user himself has to choose one. I think this user interface will fit your scenario, too.
I've found an example where radio buttons are used strato.de/linux-root-server. There's a different design used for the english website so I have to show the german one. It's about choosing between no period and 12 months.
As it's difficult to recommend one of your suggestions without knowing your users/field etc. I'd say that
it calls out for an A/B Test.
Split your visitors into two groups, show each group one version and track your conversions. That'll almost certainly answer your question which version to take.
A grid comparing all the options available with the prices is the best solution.
Image Source: http://www.bigrock.in/web-hosting/ecommerce-hosting.php
Your select option can hold the different plan prices, making it easier to compare.
Other alternative would be, using the existing layout and having the monthly option selected along with a link (In a prime area. Just below the "Buy Now" possibly.) saying, "Cheaper alternative plans available".
