Pricing research how to...

I've seen the Van Westendorp and Gabor Granger offerings but I'm not sure that what I want to do is covered by these - if it is then it's close to Gabor Granger.
I want to show respondents and image of a subscription offering to a magazine. The shop price will be displayed and then three subcription offerings
1) Trial
2) Price for one method of payment
3) Price for another method of payment
We will produce graphics that show the same display but with varying prices which I intend to present in random order. For each of 1-3 I want to ask 'How likely are you to take up this offer' on a 1-3 or 1-5 scale.
Any tips on how to go about this and how to do the analysis?
tia
Nick