If you give more info maybe I can help you out. What size boat do have? And what would you call a good setup? How many rods do you want to run at the same time?
You can use dipsies, jet divers, snap weights, and down riggers. All of which vary in price starting from $10.00 for a diver up to $600 for electric downriggers. Planer boards are a good option for getting baits away from the boat also. You can pick up a copy of "Trolling from top to bottom" which gives you a lot of good info on the trolling game.
Also, I'm in the process of upgrading some things that may be of interest to you. PM me if you're interested.
If you want to keep it simple and give yourself decent odds, get a Diawa combo outfit from Dick's sporting goods which has a line counter reel. Load up with 30# test Fireline and use a Dipsy Diver and spoons. You will be equiped for walleye and steelhead with this set up.
Boat: Im not sure the size i will be going up with my g-paw and family. He has a recreation deep v i believe. possibly 6-8 rods at a time.
Rods: I have two heavy action baitcast rod and reel sets to use.
I think ill be wanting to use, divers, or planar boards. Im going to purchase some type of spoons, and possibly use my bomber long A's, rattlin rouges, or husky jerks to troll unless anyone has some better lure choices.
Shortdrift makes a good point about the linecounter reels...you can't beat a good line counter for getting to the exact depth. You mentioned you have rods already, you may think about adding the Shakesphere line counter They are accurate enough up to 50-75 feet of line imo. They're about $15 dollars at Bass pro. Secondly, Dipsies have become the diver of choice on Erie...mostly size 1 (big ones). Pa's spoons and Michigan stingers spoons (small ones) are popular baits for trolling. You'll also need good rod holders because you're putting a lot of resistance on those rods. So figure about $20 (setup) per rod not counting the other things...(holders etc.)
Lastly, get a copy of Precision Trolling, it gives you info for dive curves for most popular cranks,
snap weight, dipsies, jet divers and much more.
Hope this helps. If you have any more questions...feel free.