THe best approach is to NOT get your chickens until you've built your coop. It's better if you don't have to build the coop in a rush, because then you're more likely to end up with something sloppy that falls apart or looks dilapidated. How did you ever get 60 chickens without setting up a coop first? That wasn't wise, but anyhow, now that you've got them you need the coop.
If you're low on funds, I recommend canvassing your neighborhood and neighbors and trying to find materials that others might be throwing away. You also will need a creative person to know how to use any materials that you do get, to construct your coop. I like the idea of the hoop coop that another contributor gave. That seems quite low cost, compared to anything you'd build of wood. I made a 4 by 6 ft coop henhouse, 6 ft high, and it cost over $1000 in materials. PVC pipe is real cheap in comparison to wood and with PVC hoops and then some type of material or tarp for a cover, you could easily make one or more low-cost henhouses. Then you could make nestboxes out of milk crates or pallets, and roosts out of sticks cut off of trees.