Baby teethers?

Sahiba • 1st baby due April 30th
There seem to be a million types of teethers out there! Any suggestions on which ones/types to buy? And how many will be needed? 
I keep hearing about Sophie the giraffe. It seems quite pricey for a teether. Is it worth it?
Also by what age should I start giving the baby a teether?
 Thanks a lot 😊