As noted, Yorkville is the most expensive part of downtown so there is something wrong. My guess is that you are looking at "York Region", which is too far from where you want to be. Try Priceline and bid 3.5* in Downtown (North and South) in the $80-100 range and get the Delta Chelsea.
Depends on the weekend - if there is something big in the financial downtown (like the Toronto Marathon in October) I would expect Yorkville to perhaps be a better bet that weekend for example. But yes, OP, do check a map!
I would prefer Yorkville for shopping, eating out, people watching etc. Downtown Yonge / Front area is great for things like Hockey Hall of Fame, CN Tower, Rogers Centre. Toronto Islands, etc.
Ultimately tho, all those things are a short cab or a few subway stops from either Yorkville or closer to the lake.