If you want a nice motel try Howard johnson on 720 north LaSalle. It is near Harry Carays and Michael Jordans. A clean area and have closed Parking. It will be about $100 in the summer.
The best part You are only about two blocks from catching the el train to Wrigley field and will arrive at Right field corner and after game Board there and go back to downtown. I have stayed there numerous times. and it is very clean around there. Look it up on the internet or call 312-664-8100. Not fancy but comfortable.
Do the name your price thing on Priceline. I got a room at the Intercontinental for $100. Move your budget up to $130 or $140 and you're pretty much guaranteed a nice 3 or 4 star downtown.
Don't stay out by O'Hare. Lame.
Within about a mile (just over) from Wrigley. Nice neighborhood, Clark street is just around the corner and you walk up in about 20 min: Boutique Hotels Lincoln Park | Chicago Business Hotel | Days Inn, Chicago, IL Very affordable.
try the Hilton Garden Inn on east Grand, less than $100 and close to the train and plenty to do in the Rush Street area. Stayed there for the Duke game and it was nice.
What is the best way to get tickets to a Cubs game? Is it best to buy it through their ticket office (mlb.com), look on craig's list/stub hub, scalp?
I use hotwire and always get the elk grove sheraton. 2 room suites in a coorporate park that is empty on weekends. It usually goes for 45 a night. Nice remodel last year (got 2 free nights because of that) with big screens, king size and a sleeper in the other room. I drive to rosemont or franklin park and take the train. You can take blue line to addison and take an express bus from there if you like