discounts on park tickets? buy now or when we're there?

[akadada]

Hi,

We head to WDW in about a week. We haven't bought our park tickets yet; planned on buying them there. We're staying offsite as well.

Is it the same price to buy them when we get there or am I better off buying them online? Are there any discounts out there for park hopper 7 days?

Thanks!