You can try the clip in hair extensions, personally I have been using them and love them. Go for high quality ones so they can last a long time. Remy grade AAA hair should be good so you can straighten them, curl them, dye them, ect.

Basically it all depends on the quality of the hair. GO for the remy grade AAA hair and it will last you a while. I got the 18" ones that are on sale now for only 135$ which is a great price for the quality