Price depends on quantity ?

Hello,
I am new here and I chose Opencart as the best free e-shop for my shop with cca 10 items,
but I really need function that the price depends on the quantity you purchase.

for example
1-10 pieces --> price= 100Euros
11-20 pieces --> price= 80Euros
....

Is it possible to do something like this ?
Can it by done as some extension.
Could you please guess how difficult it could be ?

thank you for every advice

not with current version of opencart. Although you can do something with discount option.

You will need several new tables and bunch of changes in code - all over the place. 2-3 days of work for good programmer (my guess)