Shopping cart price rule for category

[LBDV]

I would like to know how to add a new rule that will have the following effect: 

When someone adds a product from category 'X' to their shopping cart (all products in category X are 75 euro) and add a product from category 'Y' (all products in category Y are 12,95), they must get the product from category Y for free. 

Can someone please help? Thanks in advance! 

[rmccallum79 · Accepted solution]

If you know the discount to apply (12.95) then set up a price rule where ALL criteria must be met (Product 1 is in category X  AND Product 2 is in category Y) then discount FIXED 12.95?

[LBDV]

That's exactly what i thought. Maybe my criteria was wrong, but it didn't work. Now i changed some things and the discount is applied so i will leave it like that. Thanks anyway!