Q. Is it okay to purchase a one way ticket to a foreign country. My reason for doing so is that I'm not yet sure what day I'll return.
A. Increasingly, it is perfectly okay. It used to be that one-way fares were much higher than a round-trip fare, but because of airlines like WOW and Norwegian selling one-way tickets for about 1/2 the round-trip price, some other airlines are following suit.
If the route you’re considering doesn’t have a cheap one-way fare (the round-trip fare is higher), you won’t get into trouble not using the return flight, as long as you don’t do this too often, as some airlines don’t like it when passengers use this strategy. As a courtesy, you should cancel your seat on the return flight.