How to buy Soviet Army trousers?

[Kovski]

Hello, I'm looking for Soviet Army trousers for my M1943 uniform(Senior Lieutenant). I watched some photos of May, 9 in Red Square, and I did not notice differences between officer's and soldier's trousers.

Where can I find such trousers for a good price? It's not hard to see the tunic, but I rarely see the trousers alone.

PS: I'm also looking for German NVA trousers(rain cammo).