What hair straightener should I buy for very curly hair?

If I may make a suggestion, you really do not need to spend that much money for a really great hair straightener!  I myself have very curly hair!  Basically, you just need something that gets HOT.  My personal flat iron is the Heatmaster Professional Ceramics that sells for $29.99!  This iron makes my hair silky straight and I have yet to have a problem with it after 3 years!
specifics:

• Ceramic Heaters generate instant heat and instant recovery - up to 430 degreesF.
• Ceramic Plates Generate Far Infrared Heat to straighten hair from the inside out
• Negative Ions improve condition and shine
• Adjustable Temperature Dial for customized heat
• 9-ft. Professional swivel cord

The Heatmaster Professional Ceramic Flat Iron will smooth out hair and maintain that healthy shine even after styling. You get instant heat and your hair is conditioned and silky smooth to the touch.


Another goos choice is the Plugged In Tourmaline iron selling for $34.99
specifics:

• Professional model
• Moist ceramic heat with ceramic plates
• Quick-heat ceramic heaters
• Heats up to 420ºF
• Ceramic will maintain even temperature all the time
• Ceramic seals the cuticle and gives even heat distribution
• Repels humidity and locks in hair color and resists fading
• Latest ionic, ceramic tourmaline technology for smooth silky hair

Get bedazzled with the Limited Edition Plugged In Pink Gem Tourmaline Flat Iron. This limited iron features the latest ionic, ceramic tourmaline technology for sexy silky smooth hair. Far infrared heat styles hair from the inside out leaving hair softer, stronger and healthier-looking. Tourmaline is crushed then infused into plates to produce negative ions which restore moisture balance. Accelerated ionic properties style hair even faster while adding more luster and shine. Ceramic plates produce far infrared heat to style and dry hair from the inside out. Sparkling gems let you style in style!

Also good is the Jilbere de Paris porcelain curved  iron that sells for $29.99
specifics:

• Ultra-smooth curved plate causes less stress and damage to hair
• Ceramic Pulse System with 200 watts of power
• 30 heat settings, up to 230 C. /446 F.
• Instant heat, even heat distribution, no hot spots
• Cool Touch Fabric

Jilbere Ceramic Tools Porcelain Series Professional Flat Irons feature porcelain plates. Porcelain is a fine ceramic compound with greater strength and durability for precise heat distribution and state-of-the-art performance. The "diamond hard" surface allows the hair to gently glide through the plates, preventing snagging and breakage. When introduced to heat, the porcelain ceramic emits far infrared heat waves, which have longer wavelengths. Heat at this level is more easily absorbed by the hair, resulting in enhanced vitality, reduced stress, and healthier hair.

I recommend you to use a CHI hair straightener. Here you have a few good offers:

I recommend it because the auto digital feature allows you to set the temperature and the time, and the digital monitor allows you to see the temperature setting.
It comes with heat proof pouch and flat iron stand.
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This flat iron comes with nano silver particles that eliminate bacteria from appliances and promote a germ-free zone to protect the health and safety of stylists and clients alike. Provides a versatile all in one ergonomic design with flash quick heating, pure ceramic heater and convenient swivel cord.
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Ceramic coated plates for far infrared heat and negative ions - meaning healthier, shinier, smoother hair
1" plates make versatile styling easy
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