Whether you're in the market for hijab, khimar, gelee, tam, chemo-cap or kisui rosh, there are some things aside of your religious or cultural requirements to consider.  The wrong type of head covering can be uncomfortable or cause hair loss.  Some are even marketed in a culturally incorrect context.  Not to mention, some unscrupulous merchants may mark up the price unfairly.

Your Hair and Scalp

The only materials that should be close against your hair are ones that will not grab it or cause it to mat.  These are silk, light spandex, microfiber and polyester satin.  A few types of cotton or viscose/rayon and hemp may be suitable, and these will be in a tight weave of the weight of bandana material.  If you can see the spaces between the threads of the fabric easily, or the fabric is rough to the touch like heavy denim, it should not be close to your head.  You will need an additional accessory called an underscarf or a durag or spandex cap.

Size

If you are buying any kind of head covering, be mindful of the size.  The measurement should be in the description, or it should be labelled as child or adult size, if it is not obvious.  Most tube caps or similarly made underscarves and headbands will fit a child or an adult with a smaller head comfortably, but people with thick hair or larger than average heads may have trouble with them.  I have never found an elastic back 3-in-1 bandana that fit me properly.

Regular bandanas also usually come in a 22x22 square inches.  For a better fit, search for bandana 27 or xxl bandana for the 27 inch ones.

Design

Many eBay merchants carry scarves and head coverings, but some stand out in the crowd.  They have head covering styles that both meet their respective religious requirements and are stylish without being overly gaudy.  They're also well priced and ethical sellers who are interfaith friendly and ship worldwide.

Asia Factory Outlet has the normal selection, but also one piece hijab caps that will fit any size of head or face because the scarf is open in the front.  You wrap it to yourself and pin or tuck it where you like.  They also have turban caps with a roomy elastic or drawstring back that you can wear with your own scarf to cover it, or with a neck scarf.  Most of their selection is also chemo comfortable.  Whether you're Muslim, Jewish, or Christian you will find something beautiful that suits your needs here.

tenten86 has a small but wonderful selection of underscarf caps, one piece, and regular hijab.  The selection is superb in quality and practicality.  Keep an eye on this one because occasionally there are drawstring underscarf caps with built in sun visors that are large enough for those with thick hair, or even dreadlocks.  They also sell some items in lots, which is perfect for the new muhajaba (modest dresser) who wants a full selection in one convenient package.

CJ Hats specializes in Jewish and chemo comfy alopecia head coverings.  They have a great selection of snoods, berets, turbans, and fuzzy caps.  Their plain snoods are a great alternative for those who find most underscarves too small and tight.  Most of the stock is sewn by the merchant herself, who is a survivor of inflammatory breast cancer and knows how to make a truly comfortable hat from personal experience.

Rasta Tings carries a colorful and authentic selection of Rastafarian and traditional Ethiopian Coptic head wraps.  They are hand woven and of the proper weight to be worn directly on the head.  Some are slim for wear as a sash or turban, and some are wide and can be worn as a full coverage wrap.

Pricing

Be very aware of overpriced scarves and hats.  You will usually get a better price by buying from the source, but sometimes merchants will mark things higher simply because they know people often won't search a variety of terms to find what they want.

If you don't find what you need by searching hijab for a reasonable price, try searching under scarves or scarf for the style, fabric, color, and measurements in the description.

If you can sew a little, or are good with fabric glue, you may also find what you need by searching in the crafts-fabric section. 

Parting Notes

I hope that this guide has been helpful to you.  If you are a beginning modest dresser or a designer or distributor of head coverings, feel free to contact me for advice.  I don't just write about head coverings.  I wear them.