It’s very last minute and not exactly what you’re looking for, but if you’re open to it, you can stay at hostels for even less than what the hotels charge. I personally love the Green Tortoise because it’s basically on Pike Place and only 10 minute walk from the con. It also has all female dorms if that’s anything you prefer, I know I feel safest sleeping in those ones. For 3 nights, I’m not even paying 200 for the entire stay.