All CDs based on the Audio CD standard contain audio encoded with a 44,1000Hz sample rate, 16-bit stereo and uncompressed. See this Wiki entry for the technical details.
If you want to make sure the CD you are buying has this standard, look for this Compact Disc Digital Audio logo:
If the CD containing this logo has MP3 or WMA files on it, then it is an Enhanced CD, which contains a data session with these files. For example, some CDs may have bonus or demo tracks that are only playable on a PC. These tend to be DRM-crippled, e.g. to allow several playbacks only to encourage the user to buy the album with these tracks.
If the Audio CD contains WMA tracks that appear to be the same songs on the CD, then this is most likely a copy protected CD, which has a non-standard table of contents to try to prevent CD-ROM drives from being able to access the main audio session. The WMA tracks are crippled with DRM and typically will only play on the PC the tracks were authenticated on. These type of CDs are getting quite rare now due to the negative publicity they've got over the DRM restrictions, however, they tend to appear now & again in shops selling 2nd hand CDs. These generally do not have the above logo due to violatating the Red Book standard.
To get access to the uncompressed audio on an Audio CD, you need a CD ripping tool, such as Exact Audio Copy.