Well if you wanna be safe and go for springs that were actually made for a Camry, go with Megan Racing springs. Based from all of my research, Megan Racing will give you the lowest drop. I had Megan Racing springs before I got coilovers and I had no issues whatsoever. They improved my handling as well as lowered my car. Also there are, in fact, Tein springs for our Camry but Megan Racing is cheaper and will lower your car a slight bit more.
But, if you want, you can do some research to see if there are any companies that have a better bang for your buck. I checked last year and it was Megan who won. But since last year, I've come across more parts available for Camrys so maybe there is something new. Only go with a reputable name brand though i.e Tein, Megan Racing, Eibach etc. I wouldn't go for something that does not have an actual name.
Here's a link for reference:
Tein
http://www.andysautosport.com/toyota..._springs/tein/
Megan Racing
http://www.ebay.com/itm/MEGAN-SUSPEN...0f5284&vxp=mtr