DAC inbetween Macbook & MF X-150+Gradient


My wife likes to listen to Pandora, but she's not fussy about sound quality. So I have her Macbook plugged into my amp via a cheap cable. But now I realize I'm going to have to hear it more than I thought. I hate how flat is sounds so I am thinking about getting a DAC.

1) I'm interested to hear from the people who have heard an assortment of budget DACs to know their favorites.

2) Is there much difference between a good $100 DAC and a good $200ish DAC?

I have a Musical Fidelity X-150 amp and Gradient bookshelf speakers.

Thanks in advance for your advice. It's appreciated.
Before you buy cables you might consider downloading JRiver for Mac, it's only $50.00 and the output from your laptop is buffered and run from memory (delay adjustable) and you can feed that into whatever DAC you choose.

I use this into my Oppo BDP-105 and while it's no where near state of the art it's almost free compared to many digital options. Best of all your wife can control it from the laptop screen, an Android or iPhone or iPad from anywhere in the house.

I've been using this to break in my speakers, it's saved me from playing the same CD endlessly to get enough hours. LP (my favorite format) is out of the question for this job.