I'm looking to buy a 6ft spinnerbait rod for roll casting. I also want to be able to use it to throw a topwater if need be. I'd like to keep it under $100 as it's not really a rod that will be used much.  I just have an extra speed spool begging for a reel and that's really the only setup I'm missing. 

 I have one that may work for you. It is a St Croix Premier P6CM,  The rod spec are 6 foot medium power with a  fast action tip, 1/4 to 3/4 lures and 10-17 pound line.  They say fast action but it is built with a slower graphite than say a Mojo of today.   I used to fish 5 St Croix Premier rods.  They were well built and very sensitive.   These rods are still being built today.  The new ones go for $130. If it met your needs I would let it go for $60 plus actual shipping cost. 

Where do you live?  Is it anywhere near MD or one of the surrounding states?  

If you are close, we could easily meet so you could check it out. I would be happy to attach a reel (yours or mine), string it up and let you cast it. 

If you are to far away, perhaps you have a St Croix dealer nearby and can check out a modern Premier series rod.

Let me know if that interests you.  It is not easy to find a quality 6 footer these days.