I noticed a complete round trip airline ticket is cheaper than one way?

I see one way tickets for $300 while round trips are $225. I'm not certain when I'd return, so would there be some kind of penalty for buying the cheaper round top ticket. Then after I fly there, cancel my return trip. And just by a ticket when I decide to return?

You do know that at that price point, to cancel the remaining flight will cost you about the same as the price you paid. Nor will the one way flight price remain at $300, the closer to the time of the flight, the higher the price will go.

There's NO penalty. The airline already has your money, and they will probably be able to sell that seat again for even more money. People cancel tickets all the time.

You can certainly buy the cheaper round-trip ticket and cancel the return part. But you should be aware that the price of the ticket may have increased substantially by the time you decide to come home.

YES you can cancel your return portion.
DO NOT expect a refund or credit.
When you purchase your ONE WAY return it will most likely be a premium price.

Buying tickets direct from the Airline or from some fly for bargain cheap fares are our specialty dot we take your money do not have exactly the same policies.
Reason you should read the fine print for details like this. BEFORE you purchase.

You can certainly cancel your return ticket (or just not show up for it). But be aware that last-minute tickets tend to be very expensive, so if you decide to buy your actual return ticket shortly before your return trip, you will likely be paying considerably more.

No showing for the return is fine, but you would be better finalising your return dare, and booking at the same time. Most travelers do this, as it rare to find a last minute or short notice fare being good value against advanced booking.

Prices vary widely from day to day. It depends on when you actually Need to return.

If it truly is a one way trip, then yeah, I've made plenty of one way trips on round trip tickets, and you can either cancel or simply not show up for the return flight. The seat's yours no matter what, but there's no obligation that you occupy it.

Should you be staying at your destination for up to three months, then one thing I've done is set the round trip return date three months in advance. Just find out what the maximum amount of time is for the round trip, and you can prolong the trip and return 3 months - and potentially even more - from your arrival date.