Hi Heiwan,
This is all common material; it will be difficult to sell at any price.
Here in Canada, one can buy 500 USSR stamps for $25 (about 12 lat). That's from a dealer; you could probably find a better deal than that on
ebay.
You might be further ahead finding a young person who collects, or donating them to a stamp club.
That's assuming you aren't interested in collecting yourself! I do collect USSR, and find even common material like this fascinating.
Good luck!