I've recently made a pop filter by taking the top couple inches of an oatmeal box, stretching some used pantyhose over it, and then keeping it in place with rubber bands and staples. Before I stretched the pantyhose over it, I cut 2 small holes in the cardboard to stick a hanger through so I can bend it around things.

Although it isn't the prettiest thing, it works super well - and for $0 (if you already have the materials) it's better than paying 60$ for a professional thingy.
Also I don't even have a vocal mic, it's a field recorder, lol.