When choosing the charge controller for your solar set up you have a few choices you can make. For one ypu need to ask which is more important to you price or efficiency. You need to know how many amps you need as well as if you are wanting to replace your first controller later or start with what you are going to need.
So let ua start with the first question. Is the price something you worry about or not. If you answer yes to this then that will affect where you go from here. It isnt out of the question to get a budget charge controller but dont expect the efficiency or reliability. Now if you are a bare necessities person you may be fine with that. When budget shopping for your charge controller you are going to want to look for a PWM controller
These can be found between $15 to $45 depending on where you look. Most of these come in amperages between 10a and 30a and can support smaller solar set ups 10a = 2 100w solar panels and 30a = 6 100w panels.
These are pretty simple to wire due to their low wattage and amperage ability.
Now if you want to buy what you need from the get go you are going to want to get an MPPT charge controller. These are much more efficiend and better quality. These can range anywhere from $50 to $400 and can range from 10a to 80a. Kust like with the PWM controllers the 10a can handle 2 100w panels and the 80a can handle 16 100w panels. 
MPPT also come with the benefit of being able to run more than one to a circuit. The wiring for this may scare you but it really is simple just be sure not to cross your wires 
Now you may have realized that the MPPT is far superior to the PWM and you would be right but i know that not everyone is able to drop a couple hundred buck or they may have a small set up that would be fine with less. If you are still unsure about what you should get i wil simplify this as much as i can and say if you are planning on doing a caravan or rv off grid then a PWM will be plenty because you can juat run a simple inverter. However if you are wanting to do a full house you may need to buy an MPPT and a more expensive pure sine wave inverter. But most and foremost if you arent sure what you should get try to talk to someone who has done it before and do more research so you can make an informed decision
These blogs are to attempt to simplify what most view as a complex situation. Remember solar doesnt have to fry your brain it can be easy.
Happy homesteading