i have a sonoline B doppler and i love it....it is easy to use and pick up the heart beat (once the baby is high enough)
i bought mine off amazon for about $60 last year and used it my entire preg with the my daughter and im using it again with the twins....id be stressed to the max without it
I got the hi bebe, and it worked very well. Bought it online and I think it was from their own website.
i bought a Summer doppler off ebay, currently 36 weeks and still yet to hear a heartbeat. having a doppler may make you panic more if you can not find the heartbeat sometime. all the best with your pregnancy :)