Depends on what needs to be repaired, if its just the hard drive we can do reformat or take it out and replace it with a new one. Which is usually one of the common repairs for most laptop. And other replaceable parts like the superdrive, battery, memory are cheap service repairs in my shop. I have an affordable flat rate for these kinds of repairs. It will be expensive if you buy new parts for mac, if you can find surplus or used parts in Ebay then you can save a little.
I my opinion I would prefer opening a mac laptop over PC's, Macs are much more organized inside than any other laptops. There are very few moving parts or near to none. In some aspects it is more beautiful inside than the outside.