How much does chemical straightening cost?

I have thick curly/wavy frizzy hair about to armpit level and I had wanted to have thermal reconditioning, but they quoted me $800 because of the volume and length. I was told I could get it for $600 or $700 if it were cut shorter and that was about what a normal person would pay.
I opted to go with a chemical straightening that my stylist recommended for me that cost me $150 total and took about 2 hours and it caused no damage, and while it was stick straight for 2 months, I could blowdry it in half the time just with a paddle brush and run an iron over just the parts that needed it in a couple of minutes and that lasted for several months.
I was most impressed with how I could put my hair in a pony or just pull part back and it looked perftect, not frizzy like it used to, and any updo I tried was great without me having to straighten it first.

I've researched and found that the cheapest rate is about 300 bux, but usually its around 500. But just so u know, all those chemicals may damage ur hair so make sure u know the risks first. Hope i helped!

How much does chemical straightening cost? Also, if you have any sugestions of national salons with straightening procedures, I would appreciate it! Thanks :)