I got it for $170USD on eBay, in Medium size, brand new

That's pretty good considering most sizes on eBay are L or XL (much too big for me) and even higher than that in price

Hows the fit and whats your measurements? Im caught between a medium and small, im about 5'9 150.

I'm 5'7" about 155. Medium fits me slightly loose (but good). Sleeves are a good length.

If you're going for a small.... I'm going to be honest, that's going to be quite hard to find/and or expensive, because both Amazon and eBay don't have Small sizes

how to you determine for the ebay ones which are legit and which are fakes.

wow you guys really gear up when running in the cold.
my winter running wear is mostly the same as my summer. i warm up pretty quick and skip rainy days. it's not too hard to find 2 or 3 dry spots during the week and if it gets real cold i'll throw on a pullover.

the cold won't hurt your lungs. the air is just dryer so you may develop a cough, but it goes away when the lungs bring the moisture back up. it's nothing you can't adjust to