Rats, I started a long reply, and then lost it. I hate when that happens. Now it's going to be a shorter version, that's for sure!
Costs? It all depends.
Transmitters can be sonic (need to put the receiver under the water or under the ice to get the sound wave signal) or radio (signals will go through the ice, but range is limited). Costs -- I haven't looked for a while. Sonic transmitters maybe $150-400 depending on size, power, and battery life. Receiver systems maybe $2,000-4,000. Couldn't find radio transmitter prices on short notice, but the sonic prices give you some idea. We do have some receivers here. Not sure of their condition.
Crappie don't take handling very well, as I'm sure most Forum readers know. We have done three previous crappie tracking studies. In the two below, one is white crappies and one is black. Technology at that time allowed us to only implant large crappies (10.5 to 13 inch white crappies; other study is 12-13 inch black crappies).
http://pubstorage.sdstate.edu/wfs/154-F.pdf http://pubstorage.sdstate.edu/wfs/123-F.pdf Then, we did one study of nesting male black crappies that were 9-10 inches because the transmitter size had decreased. Paper link below. I don't know how much smaller they have made them since then because I haven't looked.
http://pubstorage.sdstate.edu/wfs/246-F.pdf We did these studies with surgery to implant the transmitters in the body cavity. On a later study for sauger, we actually used external attachment of radio transmitters, which might be something to try on crappies in the future.
How's that for talking around the issue??
