Best advice I think I ever got was to not worry about spending too much on trolling rods… it isn’t like you feel the tick or bite. I use an Okuma Classic GLT Downrigger rod – 7’6″ Medium light. I can tell when pulling a board if a flicker shad runs fowl… and yet it has been everything I need for salmon on Lake Michigan. Very versatile rods.
At $28 on Amazon right now, it is hard to beat. Pair it up with Convector 20 series (30 series if you want more flexibility of using on the great lakes or lead core) reels and you have everything less the line for $100.