At first time when i put money in Adwords 50$,
they are gone fast whit no good results but i put the expensive words and country.
Afther that i make a good research on more cheap,words and sellect more country where to to show my ads,and whit more 50$ i have good results and olso sales.
Try to find cheap words but olso that have impact,and try to change your campain ever time you spend money.so you will have success whit adwords.
And that is true Adwords is expesnive but have results.
I use this word and they are at a good price(cheap wordpress hosting,web hosting offers,cheap web hosting offers.)