Are there actually accommodation options in Cần Thơ, Vietnam for less than USD $10? [closed]

Here in Cần Thơ in Southern Vietnam all the usual ways I use to find cheap accommodation fail to turn up anything less than USD $10 - and that one, where I am now, is quite a bit cheaper than anything else.

I've used: • HostelBookers • HostelWorld • WikiTravel • WikiVoyage

But are there other cheaper options around that just aren't listed in any of these places?

The hotel I'm at is really fancy for $10 - private bath, hot water, even air con. But I can manage just fine with a lot less. I'm happy with a shared bathroom, bucket shower, and a fan.

I asked at a about five places in the first town over the Cambodian border and half just told me I couldn't stay. I don't know if because they don't take foreigners or because they were full. The other half were all USD $10. I gave up and continued on to Châu Đốc where I knew there was a place for $6 or $7.

Could it be related to the fact that foreigners must register with the police and tourist accommodation does that for you whereas local accommodation is not set up for it?

Are there actual guesthouses here with lower prices than the hotels?