The name of the game here is research, research, research!
For each shortlisted role find out:
How much could you expect to earn as a minimum and maximum (in your area) and what is the average salary?
Do you need to study? Is it not required, optional or necessary?
Are there other benefits, such as bonuses, working from home or being able to work for yourself etc?
Put all these details in a spreadsheet, word document or even on good old fashioned paper – you’ll need this later!