If you re willing to go for a clip hair extension make sure they do not sew your hair with it, leave it as a clip on extra hair that you could use when you want to...
If you go for the attached to hair kind you will only ruin your hair without even letting grow or breath and will lose a lot of hair.
The best way to do it is to wear the clip on extension on occasions and not let it be too tight. you could also use more than just one it will make your hair thicker and you could do layers too to make it look more real.
I don't know what brands out there but I do know that there are three kinds of extensions:
natural, semi natural( fake and natural mixed together) and fake. The most expensive is obviously the natural one.
If you want your hair to match the color then get the same tone or you could dye it with the same hair color if you want to.
I didn't really get the third question.
As I said the best ones are the natural hair and you could go for any hair color or dye both together( your real hair and the extension) with the same color but ofcourse the extension should be the same color as yours in the first place so you won't get a lighter or darker color.
Honestly, as far as I know boys hate it... but some don't even care as long as the whole package looks nice.