You can buy mature plants
just about anywhere that bedding plants
are sold, for the next couple months. (The first matter of importance is to pay attention to the type
of strawberries you buy.) If you get them right into the ground **or in planters, or whatever**
so they can get their roots established, they should start producing as soon as the weather gets nice & warm.... providing you don't get a long rainy spell, as they need lots of sun & don't like to be too wet.
If you're just starting out, here's a link to a topic from last year, with several Strawberry tips
& more links to even more information.