I don't have any experience with the referenced company... but depending upon what you're after, you might be able to get by with a men's fleece or synthetic fill vest that would fit your dog. Maybe you can find a good thrift store or Gear Swap deal, or depending on you and your dog's size, you can share the same vest (obviously at different times).
For example, my 95 lb lab wears my M's Large synthetic fill vest. It has just enough room in the chest and arm openings that he can comfortably fit in it and I just cinch up the waist around his mid section. Works great for hanging around camp. While hiking, the dog doesn't wear any kind of insulation or rain protection. We just keep moving, snack along the way and dry him off real good in camp and get his vest on him if needed.