Apple isn't in the business of giving things away. But, they do periodically provide free upgrades if the device being serviced has been repeatedly serviced, and an exact replacement isn't available.
I have also had them help on occasion when I've lost a product key, and they've helped me obtain a new key (after verifying my prior purchase).
Rarely will you find them just giving you something for free, without it being because they are liable for something.
I've had other companies offer me discounts on new products / models because I had a problem doing a particular task with my current model. And, I don't know if Apple would do that or not... It would depend on the customer service person you speak with.
When it comes to warranty repairs, I've found Apple to be extremely difficult compared to other companies I deal with. I often find it better to buy Apple products from local private companies, because there is a no questions asked return policy at most of the local stores. I can return something just because I don't like the color (and often up to 90 days). With Apple, I've had numerous DOA problems that I had to fight for weeks to get authorization for repair. So, I buy local most of the time now, and if I have a problem in the first 90-days, I just take it back and get something else. I've even had some local stores agree to provide me with free new replacements even a year or two after buying something.
Dealing with Apple is very easy when it comes to software or general questions though. They've always been great when I've called with problems that can be fixed over the phone.