I used to trap more as a teenager, but don't do it very much anymore. A couple years ago when fur prices went through the roof I got back into it for a season and ran a muskrat line. 110 conibears, 1 1/2 coilsprings, and -- for the first time ever -- some colony traps.
I'm sold on colony traps for 'rats. Those 12 traps outproduced dozens of conibears and foothold sets combined. They produced when I used them to block runs cross-wise for other traps! If fur prices go back up, my plan is to use a few 160's or 210's (single-spring 220's) and colony traps everywhere else I can.
There are guys in the Dakotas catching 5000 rats a season like that. (Protip: you can trap all public right-of-ways out there) When muskrat pelts were averaging $12 a piece a couple years ago, think about the kind of money they made for 6 weeks of hard, hard work pulling huge corn-fed 'rats out of ditches and marshes.
I wish raccoon prices would go up, since there are huge Wisconsin coons everywhere where I live now. Tons of mink, too, but with the rise of mink farms that pelt will never go back up again.
Canines are the only consistent money south of the taiga, but they're tough to catch in numbers unless that's all you do like the coyote guys on the northern plains or the fox guys in Pennsylvania.
Canadians, Russians, Scandinavians -- anyone with a long line in the subarctic can still make a living off of catching martin, wolves, wolverines, and lynx. I think global warming will probably lead to the collapse of those prices, too, someday soon.
Pic is of a book I read many times as a kid, highly recommended for any anon starting out. Also, don't forget to read your buyer's fur handling guide. (like this one:
http://www.nafa.ca/wp-content/uploads/2015/10/NAFA_PeltHandlingManual-E-web1.pdf )