My girlfriend and I have stayed at a few places on our trips up this year. With budget in mind here is our current rundown in order of our favorite to least:
Motel 6 In Milan: This one was our favorite, the price is good and the rooms seemed to be more recently renovated. They also have a working Fridge and Microwave in the rooms. (The rooms also have an interesting 60s aesthetic and hardwood floors)
Super 8 Motel in Milan: This is across the street from the Motel 6. The rooms here were nice as well. bottom floor has a back door to the rooms too which is nice for quick loading and unloading the car. This one is about as high on the list as the Motel 6, we just like the renovations at the Motel 6 a little more. (The only downside is you will be about 20 minutes from the park in either of these first two}
Magnuson East Sandusky: This was our first hotel we tried this year, the location is just a couple minutes from the park and the price is fair, so if distance is important this one if a little better than the first two. I think the only real issues here is that there is a bit of a strange smell you have to get used to (But hey its a hotel and thats usually normal) and the walls seemed a bit thin as we could hear our neighbors all night (But that could just be noisy neighbors) There are mixed reviews online, some mentioned bedbugs, but i inspected our rooms each time and never found any issues personally.
Norwalk Inn: (Farthest from the park) This was the cheapest by far, however we did not stay. Management seemed nice enough and it lookes nice on the outside, however the room we got was in pretty bad condition, dirty and pretty beat up with a non working microwave and fridge. Both my girlfriend and I didn't feel comfortable after getting there and opted for the Super 8 instead. This one was the only one under 100 a night (We were looking to save some money) but like Ding Dong said, it gets pretty dicey when you dip that low. ( we looked at a few other cheap places but also opted out)
Hope this helps, as you can see we had to do some experimenting to find a place and will likely go for the top 2 any time a trip comes up again unless we can find any better recommendations that are closer.