Most good snake keepers feed frozen/thawed (F/T), there is no reason for the general herp keeper to feed live. Most snakes have no troubles eating F/T, and if you buy from a reputable breeder, they will most likely already be eating f/t (if not, find another breeder).
It depends on the species as for the size and feeding requirements. Reptiles certainly can not be lumped into a general box, you need to do some serious researching and reading and studying and talking with herp owners before you even consider getting a reptile. They are not cuddly creatures like a kitten or bunny, they are not even considered domesticated (with the exception of the corn snake and ball python, I believe).
Search for reptile-specific forums and start reading. When you think you've found what you love, research some more. Care for these animals means caring for their every need, not just what you think is good enough (this means an appropriate habitat, feeding routine, heating and humidity, health care, etc).
Owning herps can be very rewarding, but also very expensive and heartbreaking at times. Personally when I kept reptiles, I ended up breeding my own feeders and investing in a home CO2 Chamber (to euthy the prey before they were fed). In the years I kept herps, I literally spent thousands of dollars on their care (including driving to and from a specialist herp vet in another city). It's not a simple undertaking by any means.
Sass (17), Majik (14), Bo (11), Lua (8), Baby (7), Oliver (5), Misha (5)