Some of the cheaper irons tend not to have high enough heat settings that will leave your hair pin straight for long periods of time. I use to use the conair when I was a teenager and when I got a newer, better flat iron the difference was very substantial!

If you do chose to get a lower quality iron where the plates are not up to par and the technology lacks then you could end up doing more harm than good to your hair, make sure you always use a heat protectant before applying any heat styling tools.

That being said if you do go for one of the cheaper irons then I would suggest you try wrapping your hair at night. Wrapping your hair is when you put your hair in a high ponytail and you put a satin bonnet over it and sleep with it on, that way in the morning your hair is straight and neat and hardly any styling is required. You could also try a protective style while you sleep and use a satin pillow case if you do not want to sleep with the bonnet but in my experience to keep my hair straight and neat the bonnet works best. I can keep my hair straight for about 5-6 days using this method.

Also when you take a shower try not to use very hot water, the steam and heat from the shower will make curly or wavy hair resort back to its natural state and mess up all the work you did straightening it. Use a shower cap, shower with warm water but not hot and limit your showers, the longer you spend in there the more likely your hair will steam and get wavy.

Right now I use the Cortext black series flat iron with 100% ceramic plates, it also has an ion technology to help protect your hair against heat damage. I really love this flat iron and it was only about 40-45 dollars at Winners. It glides through my hair without pulling, has a wide range heat setting and it is very good quality! It also gets my hair very straight and I have naturally very curly thick hair. If you do not have Winners where you live you can check online or check at Marshalls because they are the same chain.

Good luck