dirt cheap 
adverb & adjective informal
Extremely cheap: [as adverb]: the auctioneers let us have the stuff dirt cheap [as adjective]: a dirt-cheap price...
- These lands were then handed over at dirt-cheap prices to industrialists, miners and hoteliers or were used for creating housing enclaves for the elite, including those in the bureaucracy.
- Although the Haier brand is making inroads into the global consumer consciousness, analysts say the deciding factor for overseas buyers is still its dirt-cheap prices.
- They sell tonnes of electronics, mostly working, for dirt-cheap prices.