Budget Travel - Ultra-cheap lodging in Spain ?

We've stayed at a variety of Formula1 motels in France, i.e. the Accor 1 star brand that has the pod bathrooms. $30 per night is hard to beat. On our last trip, we discovered a similar chain called QuickPalace -- funny name, but it was also very cheap.

Now we've got a trip to Spain, but it seems that Accor has a very minimal presence. Are there are other ultra-cheap 1 star chains I should look into?

http://www.hrs.com/web3/?customerId=410736001&EXTextcmp=KNC-UK0310PKW&l=en&h_CID=C1029 you will be hard pressed to find better than these people

Not a chain, but www.hostelbookers.com can sometimes have some interesting low-cost rooms.

Romelle