Free Product w/ Order over $xxx

[mickeymouse]

Here's what I'm looking for:

 

I'm offering a new product in my line.

I would like to give my customers a free one if their order total is...say like >$20, but at the same time I want my customers to be able to purchase the product.

 

I would really love to have it so that upon checkout, if their order is over the set amount, that they would be notified on the site that their order qualifies for the free product and then re-directed to the product...

 

Is this possible or is their a contrib of this nature...I've searched everywhere and haven't been able to find anything of this sort.

 

Thanks