03 Ford Ranger 2wd 5spd manual issue

I have 03 ranger which is a 5sp manual transmission. Any way it was shifting fine the other day. And now when I went to put it into reverse it did not want to go in but when I turned the truck off. Pushed the clutch in and it went into reverse then I started the truck and backed out of the park space and them it shifted ok. Is this a clutch going out? If it is how much would it cost to fix? Any help would be great thanks. :confused:

My guess your clutch master or slave cylinder might be going bad or possible low on fluid