Go Deals - Assorted Fitted Sheet Sets Single & double sets ($5.95) Queen size ($6.95) + shipping
Cheap fitted sheets.
Please note: This merchant takes a LONG time to ship. Their products are also a hit or miss. I have been really happy with some of the things (e.g. their beach towels, high quality sheet sets, hair accessories) but extremely disappointed by blankets and the freebies (I threw all their freebies in the bin - that was how disappointed I was).
I do not personally know the quality of these sheets, but I assume they are basic. They are reliable - as in they do ship out after you have paid, but shipping is really slow (2-5 weeks!)
Also, they used to spam me constantly about all their sales (like a broken record), but weirdly enough the spam has stopped without me doing anything! Happy with that ;D