I just got the cheapest one I could find at walmart. I filled it with seed that is a mix of safflower, some smaller seed -- and, hot peppers and capsaicin, to discourage the squirrel who previously chewed all the perches off the the first feeder I got. The sparrows and finches all seem to like it.
But in the hardware store there were a number of feeders of "nyjer" seed which is smaller and I think is mainly for wild finches. Also the $5 feeder I got, has an option to flip the perches Up if using for nyjer-seed only, or down for other / mixed seeds.
I cannot picture a bird getting stuck in this particular cheap feeder. Anything is possible I guess, but my cheap one is just like a cylinder with some perches around it and a way to hang it at the top.