I've been researching hair replacement options for about five years, here's the lowdown on what your options are...
The wigs you see on
wigs.com, and the ones usually sold in retail stores, aren't really that good for extended, daily wear. They're like wearing a hat -- full caps, they cover all your existing hair. They're hot, and usually fake and wiggy looking. There are some lace-front full wigs that have the hair knotted to a very fine lace in certain areas (hairline and usually a part in the hair up top), so you can see through to the scalp a tiny bit. These are more realistic looking. If you like to mix it up or try out new hairstyles, or you're going out and want to glam it up, these full-cap pull-on wigs are just fine; but if you want realism, you've got to look elsewhere.
Human hair will look more realistic in general no matter which wig you get, but the most realism would be gained by going with a partial full-lace wig, with the hair knotted to the lace. If your hair loss is only on top, for example, you get a custom lace wig just to cover the top of your head only, coloured to match your existing hair. It can be attached with clips, however the most realism will be gained by shaving off the hair in the thinning areas totally and using an adhesive tape or glue to attach the lace directly to your skin.
The lace is a very fine synthetic mesh that virtually disappears when placed against the skin, and the really fine laces almost impossible to see unless someone is about 2" from your face with a magnifying glass. You can even pull your hair back and expose the hairline, and it looks incredibly real. They are lace, so they allow your scalp to breathe, and the rest of your head isn't covered with a wig. Hairlines can be staggered a bit along the line so they more closely match the growth patterns of real, growing hair.
There are hair clubs and places local to you that will sell these to you, they will charge you thousands for the wigs, then want to lock you into a contract for servicing it, etc. for hundreds a month. The most economical way is to order online from one of the companies that sells them, and do the attaching/detaching and cleaning yourself. They are around $600 each for the hair systems. You will need 2-3 a year, depending on how hard you are on them and what lace you get; they do lose hair over time and will need to be replaced.
Doing it yourself is of course a learning process... but there is good support from online forums and the like, and the cost savings are worth it. There is maintenance involved, but most people leave it attached for a week or two at a time, and it's about an hour of maintenance once a week once you get it all down pat.
You can check out this company...
http://www.hairdirect.com/ . I've ordered their custom fitting kit for women, and it is very well-put together, as is their site. There are others,
http://www.coolpiece.com ,
http://www.toplace.com/ , and probably others. All the ones I have listed have been around for years, and I've ordered from two of them, so I know they're not fly by night companies. I have no idea if they are trans friendly or not, but you of course don't have to volunteer that info. They do have plenty of female clients though, so they know what hair densities, etc. are best to order for women.
Hope some of this helps. If anyone has any more questions, feel free to ask...