Some deep discounts on at least a few linux-compatible titles:
X-Com Enemy Unknown Complete $25.00
Europa Universalis IV Digital Extreme Edition $11.24
Pajama Sam - No Need to Hide When its Dark Outside $1.74
Cities in Motion Collection $12.49
Freddi Fish and the Case of the Missing Kelp Seeds $1.74
Knights of Pen and Paper +1 Edition $3.74
It's been a while since I've purchased a game from Amazon but I know at least some (most?) of the titles come with Steam keys (DRM: Steam under the title). I don't know if steam keys can be obtained for the drm-free versions--please use due diligence and research before buying.