Both of them have plural forms (salaries and wages). So it just depends what you want to say. Here are some dictionary entries:
Some managers earn annual salaries of over £80,000.
people with high salaries
She's on a salary of £16,000.
Some companies pay higher wages than others.
He earns a good wage.
The wage increases will come into effect in June.
a weekly wage of $250
They’re protesting about low wages.
Do not use wages before a noun. Use wage e.g.
Wage levels in manufacturing and mining dropped again last month.