I’ve recently fallen in love with the cordless / electric jobbies but I don’t think you’ll be able to get into one of those for under $25.
Rapala makes a decent knife and they offer multiple lengths depending on the species you normally target. I’ve used that brand and been pleased. One thing I don’t really care for is the wooden handle but its not a deal breaker.
Falcon makes a good cheapo knife (under $10) that I carry with me and use all the time. Not a great blade by any means… the blade is a little too short and a bit too wide in my opinion, but the knife stays sharp and you can’t beat the price.