Character toys are an extremely popular subset of toy collecting. Competition for such toys is fierce, as many of them have cross-category appeal, for example, to collectors of comics or radio show premiums.
The famous cartoon detective Dick Tracy featured in a great tin-litho character toy made by the Marx Company in the late 1940s and early 1950s: the Dick Tracy Squad Car. It was offered in several sizes and varying degrees of deluxe-ness, from a simple palm-sized friction car to this 11 inch model with a wailing siren, working spotlight, and "gun sparks" created by a concealed flint. Mine is missing its spotlight and has a lot of play wear, but the lithography of Dick and his sidekicks is still bright and colorful.
I love the design of this toy. The characters are visible from all angles in the windows: head-on in the windshield, in profile on both sides of the car, and from the rear in the back window.
I found the Squad Car just a few years ago at an antique shop; my other Dick Tracy item has a much more interesting provenance. I was home from college one summer, helping my mom with some gardening. All of a sudden there was a "clunk" as my shovel hit something metallic in the earth. I was an anthropology/museums major, with a special interest in archaelogy, and I began excitedly yelling, "hey, we found something! Could be a treasure!" And indeed it was: my mother unearthed this Dick Tracy cap gun, made by Hubley in the late 1940s, and said: "huh. I wondered where that went to. I missed it one day little Robbie and I played cops and robbers in the yard." So...this toy was buried in my grandmother's garden for several decades. It now resides in a place of honor in my toy collection (I didn't give it back to my mom. Finders keepers, you know...).