You can buy refurbished Garmins pretty cheap at factory outlet store. Just Google it. I just got a Garmin 620 for around $160 without the heart rate monitor strap. They have about a half dozen models right now... 15, 110, 220, 305, 610, and 620.
You need to go to DCrainmaker and read his reviews to see what model you want. Frankly, some of the models are way overkill for some users. Many of my friends don't really know how to use their Garmins.
My advice: You need to decide what you want your Garmin to do and find a model that does that and not much more. The more features you add, the more difficult it becomes to work with it.
For example, my new Forerunner 620 gets good reviews and collects a ton of data. I thought I'd love it, but the data is not easily accessible. Sure, if you want distance and time, then it's on the main screen, but if you want something else... lap splits, heart rate data, cadence... you're almost forced to let it link to Garmin Connect online and look at the data online. Even then, you're forced to burrow through layers to get down to lap data. The data is buried deep in the menu on the watch, but getting to it is too much of a hassle.
I'd rather cycle through a couple of screens to see what's important to me.