First, some of the less expensive pieces are quite remarkable. The range of dogs from a manufacturer like J.J. (Jonette Jewelry) is impressive. For those interested in collecting a wide variety of breeds or humorous canine jewelry, J.J., though inexpensive, is a good choice.
J.J. Basset Hound Pin with Moving Ears
Second, both collectors and dealers may not realize how common or uncommon, a piece may be. Enamel scatter pins come in a huge range of breeds, colors, and manufacturers. There is some value in knowing that a good example of a Har enamel dog is quite a bit rarer (and worth more than) one made by Gerry's.
Third, we all start somewhere. The nice thing about collecting costume jewelry is that you can get your feet wet without drowning. For a few dollars you can start a collection and learn about condition, values, scarcity, and what you really like. A collection can always be upgraded.
Finally, collectors are often "completists" ... wanting to get a representative sample of every variation. High or low end doesn't matter, it's getting the whole range that counts.
Bottom line...when startng a dog jewelry collection, collect what you like and what you can afford!