When we bought the house in winter 2013, I put in cedar garden beds from Home depot. At about $30 for a 4×4 bed, they are not a bad deal. From experience, I can tell you now they have about a 3 year lifespan. The strawberry bed was literally falling apart this spring. I couldn’t keep the sides on the bed anymore. We tried everything except metal brackets, opting instead to just go get bigger boards.
I expanded the bed to approximately 5×5 (the boards are 5′ each) with some interesting concrete corner pieces I found at HD. I used yard bags cut up to cover the grass and cut down on weeds, then K helped me fill the gaps with new dirt. The strawberries will expand and fill those gaps soon.