We saw Tim Horton's everywherreeee in Canada and finally gave in. The prices are cheap- comparable to McDonalds coffee prices. The amount of flavor however is not comparable to Starbucks. After the 2 variations of coffees (something Mint flavored & a Caramel Latte) we had tasted watered down, we decided not to grab a snack from this place. The advertising reeled us in but the quality kept us from returning.
For cheap coffee, I would choose McDonald's over Tim Horton's. The selling point for this franchise might be that it has great, convenient locations. I cannot vouch for their baked goods however.