SeoToaster does include product set natively.
You can create a simple custom packages presentation easily like on
for instance, inserting this code in your product page template;
Then within that content container add 1 or more products that compose your product set.
You can easily have the set pricing based on the individual products prices, or set a custom pricing for it.
You can also set a discount over the automated product pricing computation by capturing a discount into the main product set "on sale" tab option for instance.