Welcome to the board huntNfish.
The Eagle Fishmark 320 is a decent unit for the money and it is right around the amount you want spend. The Lowarance X-96 is another good unit, but it is almost identical to the Eagle 320. In fact both are made by Lowrance. I am sure that the guys on the forum will come forth with more good advice. There are plenty of good Crappie fisherpersons here with tips and advice that will put you on the right track.
Keep an eye on the Crappie condo thread which has information on when we will be working on building condos and deployment dates. Come on down and join us. There is a good bunch of guys and gals working on this project. PopPop is the co-ordinator of this project, and I guarantee that when you meet him you will find a new friend and also wish that you had known him long before now. I will send you a PM with directions to the build site. Work dates will be posted on the forum. Once again, welcome aboard!
Kellog