Josephine, your 1974 USSR coin set is a standard hard collector's case package from that year. There are some variants that year that are worth more than others, but yours does not look to be the case.
This collection is probably worth around $75. Maybe a bit more, maybe a bit less. Since there is absolutely no precious metals value in these alloy coins, it's pretty much worth no more than "what someone is willing to pay for it".
That said, you shouldn't have much of a problem selling it.