Millions of people wake up every day with their credit cards in their hands. As the day goes they spend a little here and a little there. Sometimes they spend money for necessaries, sometimes for luxury and sometimes to make their life easier (i.e. save costs anywhere else)
If the average human makes like 3 transactions every day (just gussed) how hard can it really be to be the transaction for at least one of those millions of people.
What i am saying is it is very possible and not even to hard to earn some money.
A site that makes me a few hundred dollar a year compares a few glasses retailers and took a weekend to make (affiliate). Just dont stop, create services and at some point they will start to generate some money