Where to buy dust mite covers

These days you can buy dust mite covers at many retailers. Most places where bedding is sold will have dust mite covers (Target, Macy's, Bed bath and beyond, etc.). You should make sure it clearly states that it will block out dust mites. Be sure to feel the fabric since some of them can feel plasticky (hard to sleep on!). If you want something more tried and true, you can go through some online allergy retailers (see list below). The pro of using an allergy retailer is that you generally get better quality covers and they tend to last longer. The con is that they can be more expensive.

Two retailers that have good reputations are:
National Allergy Supply: http://www.natlallergy.com
and
Allergy Control Products: http://www.allergycontrol.com

*I don't get any kickbacks or perks from these companies, they are just ones I know of.