Any way to send out free downloadables?

I have some products that are download only zips. I want to be able to send out some free download links if the customer buys certain other products, sort of like giving a bonus or free gift, but still maintain the original price shown on the product.

I don't want to send just the direct link to the zip , I want to use the same abilities to set days before the download expires, and number of downloads, using the preset attributes.

Is there a way to send out a download from my end as if they have actually bought the downloadable process?

Or, is some other method best suited for this, like a unique discount code, in an example: buy product X, and get product (download only) Y and Z for free? Whereas Y and Z have a fixed price normally?

Thanks

I tested using coupon with a higher value than the item was testing the coupon on, it still required I enter a credit ard number after the coupon was acknowledged. I think this will be confusing to a customer to have to enter a CC even though I emailed them a coupon.

I also tried testing using a gift certificate emailed from the admin. I send myself an email (same mail as logged in to admin with), an email arrives with a gift certificate code.

I log back in through the emailed link, there is a notice about the gift cert showing the balance, but when I try to check out, I says invalid code. I tried sending a new code and certificate, still it says invalid code.

So far either gift cert or coupon are not looking like good solutions for me to offer bonus products if they purchase something.