Most of my bike tours are in Europe and normally I go with a buddy and we split the cost of a "bed & breakfast" room. This is good in the way that I save on the weight of the gear, but it costs a bit more money to stay in such places as opposed to camping. For example, last year, I paid on average $40.00 per night for boarding (half of the cost)...
When I bike tour in Canada, I normally camp. I had an old "Walmart" tent that is still great, but a little on the heavy side. This wasn't a problem, since I used my BOB Yak trailer and 90% of the routes I do are completely flat.
For my upcoming tour of Europe I'll be going alone and I'll be camping. I can't take my BOB yak on the plane, so a lighter tent was the way to go. I found a great deal on REI's website in the US for a "last year model" of the MSR Hubba Hubba + gear shed. In total it was $245. (Brand new is about $500). This is exactly how I wanted it, because I want to be able to put my bike in the gear shed.
What type of tents do you have when bike touring? Here's mine (not the actual tent, but exactly the same model)