To me, it boils down to what you use your computer for. I got a new $2k Macbook Pro and upgraded it to 16GB of RAM. Cheap, no, but I do web design, iPhone apps, Java programming and run it as a serve scraping stock market data. I use it a lot and get good mileage out of it. I did a cost/benefit analysis and decided to go for it.
If you want a Mac with Yosemite and don't need a laptop, take a look at the Mac mini. (
http://store.apple.com/us/mac) You're looking at a powerful little Apple machine at less than half the cost of a laptop.