guess the type of crappie rod of you want/need depends on the method of crappie fishing you're going to try or do. Just about any light action rod will work, from 4.5' on up to 14 to 16', but depends on the type of fishing. Some use open face/spinning reels, closed face, lightweight baitcaster, line counters. The different methods include, but not limited to vertical or jigging in submerged brush/tree tops, spider rigging/slow trolling, longlining (my preference), pushing cranks or pulling cranks, aka crankbaits, bandits 100/200/300's seem to be the most popular, but bomber cranks work as do most other cranks if the presentation is right. Some even cast to structure similar to bass fishing but using small jigs. If you're looking for something inexpensive, look at the cherrywood rod in a light action, 6.5 or 7' if they offer it, and a small reel, would not got with an UL reel as line capacity and size comes into play. The UL reels won't last long draggin' a big slab thru the water, the UL rods are fun as all get out to see that rod double over with a big 'un. Walmart carries the cherrywood line for $20 or so, I use the Shakespeare micro graphite 6.5' (about the same $$ as the cherrywood) with a quantum ss10 open face, 6lb hi vis line for longlining. If I pull cranks, I use an Ugly stick 7' med action rod, Okuma 15dx line counter reel with 10lb hi vis line. Get some rod holders too if state regs allow more than 1-2 rods. Pulling cranks can put some tension on the line and will wear your arms/wrists/hands out in no time flat, hence the rod holders. I don't spider rig, vertical jig or cast, too lazy I guess. Some people use up to 8 or more rods when pulling or pushing cranks, & spider riggin, so have some extra $$ for the rods/reels/rod holders, and cranks at $4+/pop per rod. I use only 2 rods (lazy as stated above).
Lots of people have their preferences, mine is longlining with jigs, and I pull cranks for giggles sometimes when longlining doesn't put fish in the boat. Others use nothing but minnows for their style, vertical jigging or spider rigging, some use a mixture, some go night fishing with minnows, bobbers and lights and do well.